Tigan

Miscellaneous Antiemetics and Antinauseants

Trimethobenzamide capsules may be administered without regard to meals.

Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.

Trimethobenzamide injection is for intramuscular administration only; do not administer intravenously.
Not for use in pediatric patients.
No dilution is necessary.
Intramuscular administration may cause pain, stinging, burning, redness and swelling at the site of injection. Such effects may be minimized by deep injection into the upper outer quadrant of the gluteal region, and by avoiding the escape of solution along the route.

seizures / Delayed / Incidence not known
coma / Early / Incidence not known
agranulocytosis / Delayed / Incidence not known
angioedema / Rapid / Incidence not known

blurred vision / Early / Incidence not known
pseudoparkinsonism / Delayed / Incidence not known
leukopenia / Delayed / Incidence not known
jaundice / Delayed / Incidence not known
hypotension / Rapid / Incidence not known

diarrhea / Early / Incidence not known
dizziness / Early / Incidence not known
headache / Early / Incidence not known
tremor / Early / Incidence not known
muscle cramps / Delayed / Incidence not known
drowsiness / Early / Incidence not known
rash / Early / Incidence not known
fever / Early / Incidence not known
injection site reaction / Rapid / Incidence not known

Tigan

Rx

Oral and parenteral antiemetic with actions similar to metoclopramide
Indicated to treat postoperative nausea/vomiting and to treat nausea associated with gastroenteritis
Not  for use in pediatric patients due to the risk of extrapyramidal symptoms and other serious side effects

300 mg PO 3 to 4 times per day as needed.

300 mg PO 3 to 4 times per day PRN. Reduce the daily dosage by increasing the dosing interval and adjust as needed based upon therapeutic response and tolerability.

200 mg IM 3 to 4 times per day as needed.

200 mg IM every 6 to 8 hours as needed. Per ACOG, trimethobenzamide is a third-line pharmacologic option if the patient is still experiencing persistent symptoms after a trial of nonpharmacologic options and other pharmacologic options (e.g., vitamin B6, doxylamine, promethazine, prochlorperzine, dimenhydrinate, diphenhydramine).

†Indicates off-label use

Use caution; specific guidelines for dosage adjustments in hepatic impairment are not available. Do not use in patients with jaundice or a history of trimethobenzamide-induced jaundice.

CrCl greater than 70 mL/minute: No dosage adjustment needed.
CrCl  70 mL/minute or less: Reduce the daily dosage by increasing the dosing interval and adjust as needed based upon therapeutic response and tolerability.

Alprazolam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Amikacin: (Minor) Because of trimethobenzamide's antiemetic pharmacology, the drug may effectively mask dizziness, tinnitus, or vertigo that are associated with ototoxicity induced by various medications, including the aminoglycosides. Clinicians should be aware of this potential interaction and take it into consideration when monitoring for aminoglycoside-induced side effects.
Aminoglycosides: (Minor) Because of trimethobenzamide's antiemetic pharmacology, the drug may effectively mask dizziness, tinnitus, or vertigo that are associated with ototoxicity induced by various medications, including the aminoglycosides. Clinicians should be aware of this potential interaction and take it into consideration when monitoring for aminoglycoside-induced side effects.
Anticholinergics: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Anxiolytics; Sedatives; and Hypnotics: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like anxiolytics, sedatives and hypnotics, may potentiate the effects of either trimethobenzamide or the anxiolytics, sedatives and hypnotics.
Apomorphine: (Moderate) Because apomorphine may cause somnolence or dizziness, monitor for additive sedation or dizziness when trimethobenzamide or other sedating anti-emetics are used with apomorphine.
Atropine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Atropine; Difenoxin: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Barbiturates: (Moderate) The concurrent use of trimethobenzamide with barbiturates may potentiate the CNS effects of either trimethobenzamide or the barbiturate.
Belladonna; Opium: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Benzodiazepines: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Benztropine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Budesonide; Glycopyrrolate; Formoterol: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Buprenorphine: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like buprenorphine, may potentiate the effects of either trimethobenzamide or buprenorphine.
Buprenorphine; Naloxone: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like buprenorphine, may potentiate the effects of either trimethobenzamide or buprenorphine.
Buspirone: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like buspirone, may potentiate the effects of either trimethobenzamide or buspirone.
Butorphanol: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, such as butorphanol, may potentiate the effects of either trimethobenzamide or the other medication.
Calcium, Magnesium, Potassium, Sodium Oxybates: (Major) Sodium oxybate should not be used in combination with CNS depressants. Additive CNS depressant effects may be possible when sodium oxybate is used concurrently with drugs like trimethobenzamide.
Chlordiazepoxide: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Chlordiazepoxide; Amitriptyline: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Chlordiazepoxide; Clidinium: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine. (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Chlorpromazine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Clonazepam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Clorazepate: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Codeine; Phenylephrine; Promethazine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Codeine; Promethazine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Diazepam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Dicyclomine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Diphenoxylate; Atropine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Dronabinol: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, such as dronabinol, may potentiate the effects of either trimethobenzamide or dronabinol.
Droperidol: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like droperidol, may potentiate the effects of either trimethobenzamide or droperidol.
Estazolam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Ethanol: (Major) Advise patients to avoid alcohol consumption while taking CNS depressants. Alcohol consumption may result in additive CNS depression.
Flavoxate: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Fluphenazine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Flurazepam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Gentamicin: (Minor) Because of trimethobenzamide's antiemetic pharmacology, the drug may effectively mask dizziness, tinnitus, or vertigo that are associated with ototoxicity induced by various medications, including the aminoglycosides. Clinicians should be aware of this potential interaction and take it into consideration when monitoring for aminoglycoside-induced side effects.
Glycopyrrolate: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Glycopyrrolate; Formoterol: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Homatropine; Hydrocodone: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Hyoscyamine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Indacaterol; Glycopyrrolate: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Ipecac: (Major) Ipecac has been shown to be effective in producing emesis in patients who have ingested antiemetics, provided ipecac is given promptly (usually within 1 hour of antiemetic consumption). If ipecac is administered after antiemetic therapy has begun to exert therapeutic effects, ipecac may be less effective. It is suggested the irritating GI effects of ipecac lead to emesis following antiemetic consumption.
Lorazepam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Methscopolamine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Midazolam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Nabilone: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression like nabilone may potentiate the effects of either medication.
Nalbuphine: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like nalbuphine, may potentiate the effects of either trimethobenzamide or nalbuphine.
Neostigmine; Glycopyrrolate: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Opiate Agonists: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like opiate agonists, may potentiate the effects of either trimethobenzamide or the opiate agonist.
Oxazepam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Oxybutynin: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Paromomycin: (Minor) Because of trimethobenzamide's antiemetic pharmacology, the drug may effectively mask dizziness, tinnitus, or vertigo that are associated with ototoxicity induced by various medications, including the aminoglycosides. Clinicians should be aware of this potential interaction and take it into consideration when monitoring for aminoglycoside-induced side effects.
Pentazocine: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like pentazocine, may potentiate the effects of either trimethobenzamide or pentazocine.
Pentazocine; Naloxone: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like pentazocine, may potentiate the effects of either trimethobenzamide or pentazocine.
Perphenazine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Perphenazine; Amitriptyline: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Phenothiazines: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Plazomicin: (Minor) Because of trimethobenzamide's antiemetic pharmacology, the drug may effectively mask dizziness, tinnitus, or vertigo that are associated with ototoxicity induced by various medications, including the aminoglycosides. Clinicians should be aware of this potential interaction and take it into consideration when monitoring for aminoglycoside-induced side effects.
Prochlorperazine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Promethazine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Promethazine; Dextromethorphan: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Promethazine; Phenylephrine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Propantheline: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Quazepam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Remimazolam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Scopolamine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Sedating H1-blockers: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the sedating h1-blockers, may potentiate the effects of either trimethobenzamide or the sedating h1-blocker.
Sodium Oxybate: (Major) Sodium oxybate should not be used in combination with CNS depressants. Additive CNS depressant effects may be possible when sodium oxybate is used concurrently with drugs like trimethobenzamide.
Streptomycin: (Minor) Because of trimethobenzamide's antiemetic pharmacology, the drug may effectively mask dizziness, tinnitus, or vertigo that are associated with ototoxicity induced by various medications, including the aminoglycosides. Clinicians should be aware of this potential interaction and take it into consideration when monitoring for aminoglycoside-induced side effects.
Temazepam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Teniposide: (Moderate) Acute central nervous system (CNS) depression, hypotension, and metabolic acidosis have been observed in patients receiving investigational infusions of high-dose teniposide who were pretreated with antiemetics with CNS-depressant activities (e.g., phenothiazine and related antiemetics). The depressant effects of the antiemetic agents and the alcohol content of the teniposide formulation may place patients receiving higher than recommended doses of teniposide at risk for central nervous system depression.
Thioridazine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Tobramycin: (Minor) Because of trimethobenzamide's antiemetic pharmacology, the drug may effectively mask dizziness, tinnitus, or vertigo that are associated with ototoxicity induced by various medications, including the aminoglycosides. Clinicians should be aware of this potential interaction and take it into consideration when monitoring for aminoglycoside-induced side effects.
Triazolam: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Trifluoperazine: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression such as the phenothiazines may potentiate drowsiness or other common side effects of either medication. In addition, the administration of trimethobenzamide to patients who have recently received CNS-depressive drugs has resulted in opisthotonus, seizures, coma, and extrapyramidal symptoms.
Trihexyphenidyl: (Moderate) Trimethobenzamide has CNS depressant effects and may cause drowsiness. The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.
Trospium: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the anticholinergics, may potentiate the effects of either trimethobenzamide or the anticholinergic.

Tebamide/Tigan/Trimazide/Trimethobenzamide/Trimethobenzamide Hydrochloride Rectal Supp: 200mg
Tigan/Trimethobenzamide/Trimethobenzamide Hydrochloride Intramuscular Inj Sol: 1mL, 100mg
Tigan/Trimethobenzamide/Trimethobenzamide Hydrochloride Oral Cap: 300mg

1200 mg/day PO; or 800 mg/day IM or PR.

1200 mg/day PO; or 800 mg/day IM or PR.

(weight 13.6—40.9 kg): 800 mg/day PO or PR.

 (weight 13.6—40.9 kg): 800 mg/day PO or PR or 15 mg/kg/day PO or PR.
 (weight < 13.6 kg): 400 mg/day PR or 15 mg/kg/day PR.

Not indicated by any route.

The mechanism of action of trimethobenzamide as determined in animals is obscure, but may involve the chemoreceptor trigger zone (CTZ), an area in the medulla oblongata through which emetic impulses are conveyed to the vomiting center; direct impulses to the vomiting center apparently are not similarly inhibited. In dogs pretreated with trimethobenzamide, the emetic response to apomorphine is inhibited, while little or no protection is afforded against emesis induced by intragastric copper sulfate.

Trimethobenzamide is administered orally, intramuscularly, and rectally. 
 
Distribution of the drug into human body fluids and tissues has not been determined. Animal data suggest that trimethobenzamide and its metabolites are distributed mainly into the liver, kidneys, and lungs. Trimethobenzamide is generally cleared from the blood within 2 hours after a single dose; however, measurable concentrations may persist for over 24 hours in some patients. The exact route of metabolism in humans has not been clearly established. In animals, trimethobenzamide is metabolized primarily in the liver to the N-desmethyl and N-oxide metabolites and excreted in urine and feces (via biliary elimination). In humans, approximately 30—50% of a single dose is excreted in urine as unchanged drug within 48—72 hours following administration; 20% of an administered dose is excreted within 24 hours.

Following oral administration, the onset of action occurs within 10—40 minutes and lasts for approximately 3—4 hours. The relative systemic bioavailability of an oral dose is about 60% that of an IM dose; plasma concentrations of trimethobenzamide attained after a 400-mg oral dose are approximately equivalent to those attained following a 200-mg IM dose.

After IM injection, the onset of action of trimethobenzamide is within 15—35 minutes and persists for 2—3 hours.

Rectal Route
The onset and duration of action of trimethobenzamide following rectal administration is not known.

The use of trimethobenzamide during pregnancy should only be considered when non-drug measures to control vomiting have failed and the risk-benefit ratio for the patient and fetus has been determined. The limited available data with trimethobenzamide in pregnant women are not sufficient to inform a drug-associated risk for major birth defects and miscarriage. Animal studies suggest no teratogenic risk. In one human study from the 1970s, the incidence of severe congenital defects was increased in trimethobenzamide-exposed infants compared to non-treated controls, but the use of other antiemetics in some patients may have influenced the results of the study. The authors concluded that the risk of congenital malformations due to trimethobenzamide was low. Other case-control studies have been published which have reported no increased incidence in malformations during human pregnancy. The American College of Obstetricians and Gynecologists (ACOG) include trimethobenzamide as a third-line pharmacologic treatment option for nausea and vomiting of pregnancy in patients who have failed other primary and secondary therapies but for whom dehydration is not evident.

There are no data available on the use of trimethobenzamide in human milk, the effects of trimethobenzamide on the breastfed infant or the effects of the drug on milk production. The molecular weight of the drug is within the range that would be expected to pass into breast milk. An antiemetic such as prochlorperazine or promethazine may be preferred when short-term antiemetic therapy is necessary in the mother. Occasional short-term use is probably compatible with posing little risk to a nursing infant. However, regardless of agent chosen, if multiple doses are to be used the infant should be monitored for excess sedation or other adverse effects. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.