DRUG INTERACTIONS
Acetaminophen; Caffeine; Dihydrocodeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Acetaminophen; Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Acetaminophen; Hydrocodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Acetaminophen; Oxycodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Acetaminophen; Pentazocine: (Moderate) Concurrent use of cetirizine/levocetirizine with pentazocine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Alfentanil: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Alprazolam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Amobarbital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Amoxapine: (Moderate) Concurrent use of cetirizine/levocetirizine with heterocyclic antidepressants should generally be avoided. Coadministration may increase the risk of anticholinergic and CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive anticholinergic effects, sedation, and somnolence.
Apomorphine: (Moderate) Concurrent use of cetirizine/levocetirizine with apomorphine should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Aripiprazole: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Asenapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Aspirin, ASA; Butalbital; Caffeine: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Aspirin, ASA; Butalbital; Caffeine; Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Aspirin, ASA; Caffeine; Orphenadrine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Aspirin, ASA; Carisoprodol: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Aspirin, ASA; Carisoprodol; Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Aspirin, ASA; Oxycodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Atropine: (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Atropine; Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Atropine; Difenoxin: (Moderate) Concurrent administration of diphenoxylate/difenoxin with cetirizine can potentiate the CNS-depressant effects of diphenoxylate/difenoxin. Use caution during coadministration. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Atropine; Edrophonium: (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
atypical antipsychotic: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Baclofen: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Barbiturates: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Belladonna; Opium: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and belladonna use. Concomitant use may result in additive anticholinergic adverse effects.
Benzhydrocodone; Acetaminophen: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Benzodiazepines: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
Benztropine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and benztropine use. Concomitant use may result in additive anticholinergic adverse effects.
Brexpiprazole: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Budesonide; Glycopyrrolate; Formoterol: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
Buprenorphine: (Major) Reserve concomitant use of buprenorphine and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Buprenorphine; Naloxone: (Major) Reserve concomitant use of buprenorphine and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Butabarbital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Butalbital; Acetaminophen: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Butalbital; Acetaminophen; Caffeine: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Butalbital; Acetaminophen; Caffeine; Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Butorphanol: (Moderate) Concurrent use of cetirizine/levocetirizine with butorphanol should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Calcium, Magnesium, Potassium, Sodium Oxybates: (Moderate) Concurrent use of cetirizine/levocetirizine with sodium oxybate should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Cannabidiol: (Moderate) Concurrent use of cetirizine/levocetirizine with cannabidiol should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Capsaicin; Metaxalone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Carbidopa; Levodopa; Entacapone: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Cariprazine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Carisoprodol: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Celecoxib; Tramadol: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Cenobamate: (Moderate) Monitor for excessive sedation and somnolence during coadministration of cenobamate and cetirizine. Concurrent use may result in additive CNS depression.
Chlordiazepoxide: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Chlordiazepoxide; Amitriptyline: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Chlordiazepoxide; Clidinium: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Chlorpheniramine; Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Chlorpheniramine; Hydrocodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Chlorthalidone; Clonidine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and clonidine due to the risk for additive CNS depression.
Chlorzoxazone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Clonazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Clonidine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and clonidine due to the risk for additive CNS depression.
Clorazepate: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Clozapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Codeine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Codeine; Guaifenesin: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Codeine; Guaifenesin; Pseudoephedrine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Codeine; Phenylephrine; Promethazine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Codeine; Promethazine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
COMT inhibitors: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Cyclobenzaprine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Dantrolene: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Coadministration of cetirizine and ritonavir resulted in a 42% increase in the AUC, 53% increase in half-life, and 29% decrease in clearance of cetirizine. Cetirizine did not alter ritonavir disposition.
Desloratadine: (Minor) Although desloratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of desloratadine with CNS depressants such as other H1-blockers.
Desloratadine; Pseudoephedrine: (Minor) Although desloratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of desloratadine with CNS depressants such as other H1-blockers.
Deutetrabenazine: (Moderate) Concurrent use of cetirizine/levocetirizine with deutetrabenazine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Dexmedetomidine: (Moderate) Concurrent use of cetirizine/levocetirizine with dexmedetomidine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of dexmedetomidine; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
Diazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Dicyclomine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and dicyclomine use. Concomitant use may result in additive anticholinergic adverse effects.
Diphenoxylate; Atropine: (Moderate) Concurrent administration of diphenoxylate/difenoxin with cetirizine can potentiate the CNS-depressant effects of diphenoxylate/difenoxin. Use caution during coadministration. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Dronabinol: (Moderate) Additive drowsiness may occur if cetirizine/levocetirizine is administered with other drugs that depress the CNS, including dronabinol.
Droperidol: (Moderate) Concurrent use of cetirizine/levocetirizine with droperidol should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Entacapone: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Esketamine: (Moderate) Closely monitor patients receiving esketamine and cetirizine for sedation and other CNS depressant effects. Instruct patients who receive a dose of esketamine not to drive or engage in other activities requiring alertness until the next day after a restful sleep.
Estazolam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Eszopiclone: (Moderate) Concurrent use of cetirizine/levocetirizine with eszopiclone should generally be avoided. Concurrent use of eszopiclone with other CNS depressants increases the risk for CNS depression and complex sleep-related behaviors (e.g., driving, talking, eating, or performing other activities while not fully awake). If concurrent use is necessary, patients should be instructed to contact their provider immediately if these symptoms or behaviors occur.
Etomidate: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
Fenfluramine: (Moderate) Monitor for excessive sedation and somnolence during coadministration of fenfluramine and cetirizine. Concurrent use may result in additive CNS depression.
Fentanyl: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Flavoxate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Flibanserin: (Moderate) Concurrent use of cetirizine/levocetirizine with flibanserin should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Flurazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Gabapentin: (Moderate) Monitor for respiratory depression and sedation during concomitant cetirizine and gabapentin use; consider starting gabapentin at a low dose. Concomitant use increases the risk for additive CNS depression.
General anesthetics: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
Glycopyrrolate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
Glycopyrrolate; Formoterol: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
Guaifenesin; Hydrocodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Guaifenesin; Hydrocodone; Pseudoephedrine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Guanfacine: (Moderate) Concurrent use of cetirizine/levocetirizine with guanfacine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Haloperidol: (Moderate) Concurrent use of cetirizine/levocetirizine with haloperidol should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Heparin: (Minor) Antihistamines may partially counteract the anticoagulant actions of heparin, according to the product labels. However, this interaction is not likely of clinical significance since heparin therapy is adjusted to the partial thromboplastin time (aPTT) and other clinical parameters of the patient.
Heterocyclic antidepressants: (Moderate) Concurrent use of cetirizine/levocetirizine with heterocyclic antidepressants should generally be avoided. Coadministration may increase the risk of anticholinergic and CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive anticholinergic effects, sedation, and somnolence.
Homatropine; Hydrocodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and homatropine use. Concomitant use may result in additive anticholinergic adverse effects.
Hydrochlorothiazide, HCTZ; Methyldopa: (Moderate) Concurrent use of cetirizine/levocetirizine with methyldopa should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Hydrocodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Hydrocodone; Ibuprofen: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Hydrocodone; Pseudoephedrine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Hydromorphone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Hyoscyamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
Ibuprofen; Oxycodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Iloperidone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Indacaterol; Glycopyrrolate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
Isocarboxazid: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and monoamine oxidase inhibitors (MAOIs). Concomitant use may result in additive CNS depression or anticholinergic effects.
Isoflurane: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
Ketamine: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
Lemborexant: (Moderate) Monitor for excessive sedation and somnolence during coadministration of lemborexant and cetirizine. Dosage adjustments of lemborexant and cetirizine may be necessary when administered together because of potentially additive CNS effects. The risk of next-day impairment, including impaired driving, is increased if lemborexant is taken with other CNS depressants.
Levorphanol: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Lofexidine: (Moderate) Concurrent use of cetirizine/levocetirizine with lofexidine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Lopinavir; Ritonavir: (Moderate) Coadministration of cetirizine and ritonavir resulted in a 42% increase in the AUC, 53% increase in half-life, and 29% decrease in clearance of cetirizine. Cetirizine did not alter ritonavir disposition.
Loratadine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Loratadine; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Lorazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Loxapine: (Moderate) Concurrent use of cetirizine/levocetirizine with loxapine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Lumateperone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Lurasidone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Maprotiline: (Moderate) Concurrent use of cetirizine/levocetirizine with heterocyclic antidepressants should generally be avoided. Coadministration may increase the risk of anticholinergic and CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive anticholinergic effects, sedation, and somnolence.
Melatonin: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and melatonin due to the risk for additive CNS depression.
Meperidine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Meperidine; Promethazine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Meprobamate: (Moderate) Concurrent use of cetirizine/levocetirizine with meprobamate should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Metaxalone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Methadone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
Methohexital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Methscopolamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and methscopolamine use. Concomitant use may result in additive anticholinergic adverse effects.
Methyldopa: (Moderate) Concurrent use of cetirizine/levocetirizine with methyldopa should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Midazolam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Mirtazapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and mirtazapine due to the risk for additive CNS depression.
Molindone: (Moderate) Concurrent use of cetirizine/levocetirizine with molindone should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Monoamine oxidase inhibitors: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and monoamine oxidase inhibitors (MAOIs). Concomitant use may result in additive CNS depression or anticholinergic effects.
Morphine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Morphine; Naltrexone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Nabilone: (Moderate) Additive drowsiness may occur if cetirizine or levocetirizine is administered with other drugs that depress the CNS, such as nabilone.
Nalbuphine: (Moderate) Concurrent use of cetirizine/levocetirizine with nalbuphine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Nefazodone: (Moderate) Concurrent use of cetirizine/levocetirizine with nefazodone should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Nirmatrelvir; Ritonavir: (Moderate) Coadministration of cetirizine and ritonavir resulted in a 42% increase in the AUC, 53% increase in half-life, and 29% decrease in clearance of cetirizine. Cetirizine did not alter ritonavir disposition.
Olanzapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Olanzapine; Fluoxetine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Olanzapine; Samidorphan: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Oliceridine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Coadministration of cetirizine and ritonavir resulted in a 42% increase in the AUC, 53% increase in half-life, and 29% decrease in clearance of cetirizine. Cetirizine did not alter ritonavir disposition.
Opiate Agonists: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Opicapone: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Orphenadrine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Oxazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Oxybutynin: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and oxybutynin use. Concomitant use may result in additive anticholinergic adverse effects.
Oxycodone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Oxymorphone: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Paliperidone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Pentazocine: (Moderate) Concurrent use of cetirizine/levocetirizine with pentazocine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Pentazocine; Naloxone: (Moderate) Concurrent use of cetirizine/levocetirizine with pentazocine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Pentobarbital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Perampanel: (Moderate) Concurrent use of cetirizine/levocetirizine with perampanel should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Phenelzine: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and monoamine oxidase inhibitors (MAOIs). Concomitant use may result in additive CNS depression or anticholinergic effects.
Phenobarbital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and scopolamine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Pimavanserin: (Moderate) Concurrent use of cetirizine/levocetirizine with pimavanserin should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Pimozide: (Moderate) Concurrent use of cetirizine/levocetirizine with pimozide should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Pramipexole: (Moderate) Concurrent use of cetirizine/levocetirizine with pramipexole should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Pregabalin: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and pregabalin due to the risk for additive CNS depression.
Primidone: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Propantheline: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and propantheline use. Concomitant use may result in additive anticholinergic adverse effects.
Propofol: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
Quazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Quetiapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Ramelteon: (Moderate) Concurrent use of cetirizine/levocetirizine with ramelton should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Rasagiline: (Moderate) Concurrent use of cetirizine/levocetirizine with rasagiline should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Remifentanil: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Remimazolam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Risperidone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Ritonavir: (Moderate) Coadministration of cetirizine and ritonavir resulted in a 42% increase in the AUC, 53% increase in half-life, and 29% decrease in clearance of cetirizine. Cetirizine did not alter ritonavir disposition.
Ropinirole: (Moderate) Concurrent use of cetirizine/levocetirizine with ropinirole should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Rotigotine: (Moderate) Concurrent use of cetirizine/levocetirizine with rotigotine should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Safinamide: (Moderate) Concurrent use of cetirizine/levocetirizine with safinamide should generally be avoided because of the possibility of additive sedative effects. Dopaminergic agents have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Scopolamine: (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and scopolamine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Secobarbital: (Moderate) Concurrent use of cetirizine/levocetirizine with barbiturates should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Sedating H1-blockers: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and sedating H1-blockers. Concomitant use may result in additive CNS depression or anticholinergic effects.
Selegiline: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and selegiline due to the risk for additive CNS depression.
Sevoflurane: (Moderate) Concurrent use of cetirizine/levocetirizine with general anesthetics should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. CNS depression is a desired effect of general anesthetics; however, concurrent use with a CNS depressant may prolong recovery. If concurrent use is necessary, monitor patients closely.
Sincalide: (Moderate) Sincalide-induced gallbladder ejection fraction may be affected by concurrent medications, including H1-blockers. False study results are possible; thorough patient history is important in the interpretation of procedure results.
Skeletal Muscle Relaxants: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Sodium Oxybate: (Moderate) Concurrent use of cetirizine/levocetirizine with sodium oxybate should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Stiripentol: (Moderate) Concurrent use of cetirizine/levocetirizine with stiripentol should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Sufentanil: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Suvorexant: (Moderate) Concurrent use of cetirizine/levocetirizine with suvorexant should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Tapentadol: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Tasimelteon: (Moderate) Concurrent use of cetirizine/levocetirizine with tasimelteon should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Temazepam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Tetrabenazine: (Moderate) Concurrent use of cetirizine/levocetirizine with tetrabenazine should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Thalidomide: (Moderate) Concurrent use of cetirizine/levocetirizine with thalidomide should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Theophylline, Aminophylline: (Minor) Large doses of aminophylline may reduce the clearance of cetirizine/levocetirizine. Monitor the patient clinically for an altered response to cetirizine/levocetirizine if coadministered with aminophylline. (Minor) Large doses of theophylline may reduce the clearance of cetirizine/levocetirizine. Monitor the patient clinically for increased cetirizine/levocetirizine-related adverse effects if coadministered with theophylline.
Thiothixene: (Moderate) Concurrent use of cetirizine/levocetirizine with thiothixene should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Tolcapone: (Moderate) Caution is recommended during concurrent use of cetirizine or levocetirizine with COMT inhibitors because of the possibility for additive sedative effects. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Tramadol: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Tramadol; Acetaminophen: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Tranylcypromine: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and monoamine oxidase inhibitors (MAOIs). Concomitant use may result in additive CNS depression or anticholinergic effects.
Trazodone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and trazodone due to the risk for additive CNS depression.
Triazolam: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Tricyclic antidepressants: (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Trihexyphenidyl: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant cetirizine and trihexyphenidyl use. Concomitant use may result in additive anticholinergic adverse effects.
Trospium: (Moderate) Dry mouth and drowsiness may occur in patients receiving cetirizine/levocetirizine; caution may be necessary during concomitant use of cetirizine/levocetirizine with the antimuscarinics.
Valerian, Valeriana officinalis: (Moderate) Concurrent use of cetirizine/levocetirizine with valerian should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Valproic Acid, Divalproex Sodium: (Moderate) Concurrent use of cetirizine/levocetirizine with valproic acid should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence.
Zaleplon: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and zaleplon due to the risk for additive CNS depression and next-day psychomotor impairment; dose adjustments may be necessary.
Ziprasidone: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of atypical antipsychotics and cetirizine due to the risk for additive CNS depression.
Zolpidem: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and zolpidem due to the risk for additive CNS depression and next-day psychomotor impairment; dose adjustments may be necessary. Limit the dose of Intermezzo sublingual tablets to 1.75 mg/day.