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Oral Administration

To assist expectoration, patients should have an adequate intake of fluids while taking guaifenesin.

Oral Solid Formulations

Extended-release tablets: Swallow whole; do not crush, break, or chew. Take with a full glass of water. May be given with or without food.
Oral granules: Open packet, sprinkle entire contents onto tongue, and swallow. For best taste, do not chew granules. Liquid is not necessary for administration.

Oral Liquid Formulations

Oral solutions: Administer using a calibrated measuring device to ensure accurate dosage.

Adverse Reactions

nephrolithiasis / Delayed / Incidence not known


headache / Early / Incidence not known
diarrhea / Early / Incidence not known
abdominal pain / Early / Incidence not known
vomiting / Early / Incidence not known
nausea / Early / Incidence not known
rash / Early / Incidence not known
dizziness / Early / Incidence not known
drowsiness / Early / Incidence not known

Common Brand Names

AllFen, AllFen Jr, Altarussin, Altorant, Ambi, Amibid LA, Bidex, Chest Congestion Relief, Cough, Diabetic Tussin, Diabetic Tussin EX, Diabetic Tussin Mucus Relief, Drituss G, Duratuss G, ElixSure EX, Fenesin, Ganidin NR, GERI-TUSSIN, Gua SR, Guaidrine G, Guaifenex G, Guaifenex LA, Guiatuss, Humibid E, Humibid LA, Iophen-NR, Liquibid, Miltuss EX, Mucinex, Mucinex Children's, Mucinex Children's Chest Congestion, Mucinex Fast-Max Chest Congestion, Muco-Fen, Mucosa, Mucus + Chest Congestion, Mucus ER, Mucus Relief, Mucus Relief Children's, MucusRelief DM, Naldecon, Organ-1 NR, Organidin NR, Q-Bid LA, Q-Tussin, Respa-GF, Robafen, Robafen Congestion, Robitussin, Robitussin Mucus + Chest Congestion, Scot-Tussin Expectorant, Siltussin DAS, Siltussin Diabetic DAS-Na, Siltussin SA, TUSNEL-EX, Xpect

Dea Class



Oral expectorant used for cough to loosen and aid in the clearance of mucus
Not beneficial for cough suppression
Available in nonprescription (OTC) and prescription products

Dosage And Indications
For the treatment of cough associated with colds and minor upper respiratory tract infections and for loosening phlegm and thin bronchial secretions to aid in clearing bronchial passages and making coughs more productive. Oral dosage (immediate-release capsules or tablets) Adults, Adolescents, and Children 12 years and older

200 to 400 mg PO every 4 hours as needed. Max: 6 doses/day (2400 mg/day).

Oral dosage (extended-release or biphasic capsules or tablets) Adults, Adolescents, and Children 12 years and older

600 to 1200 mg PO every 12 hours as needed. Max: 2400 mg/day PO.

Oral dosage (oral solutions or syrups) Adults and Adolescents

200 to 400 mg PO every 4 hours as needed. Max: 2400 mg/day PO.

Children 6 to 11 years

100 to 200 mg PO every 4 hours as needed. Max: 1200 mg/day PO.

Children 2 to 5 years

50 to 100 mg PO every 4 hours as needed. Max: 600 mg/day PO.

Oral dosage (oral granule packets with guaifenesin 100 mg per packet; e.g., Mucinex Children's Chest Congestion Expectorant Mini-Melts) Adults, Adolescents, and Children 12 years and older

2 to 4 packets PO every 4 hours as needed. Do not exceed 6 doses/24 hours.

Children 6 to 11 years

1 to 2 packets PO every 4 hours as needed. Do not exceed 6 doses/24 hours.

Children 4 to 5 years

1 packet PO every 4 hours as needed. Do not exceed 6 doses/24 hours.

For the treatment of cervical factor infertility†, including cervical mucus thickening induced by clomiphene treatment. Oral dosage (immediate release, alcohol-free formulations) Adult non-pregnant females

A dosage of 200 mg PO 3 times daily during the follicular phase of the menstrual cycle (i.e., until ovulation) has been reported to be effective at thinning cervical secretions for the purpose of enhancing sperm penetration. When used with clomiphene treatment, guaifenesin use typically follows the last dose of clomiphene and continues until ovulation. Although widely reported as a potential usage, no controlled clinical trials exist. Use for this purpose is limited to the prescription by a qualified fertility specialist. Alcohol-free products should be chosen.

†Indicates off-label use

Dosing Considerations
Hepatic Impairment

No dosage adjustment is needed. Guaifenesin is primarily renally eliminated.

Renal Impairment

Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed.

Drug Interactions

There are no drug interactions associated with Guaifenesin products.

How Supplied

AllFen/AllFen Jr/Bidex/Diabetic Tussin Mucus Relief/Guaifenesin/Humibid E/Liquibid/Mucosa/Mucus Relief/MucusRelief DM/Organ-1 NR/Organidin NR/Xpect Oral Tab: 200mg, 400mg
Altarussin/Altorant/Chest Congestion Relief/Cough/Diabetic Tussin/Diabetic Tussin EX/Diabetic Tussin Mucus Relief/ElixSure EX/Ganidin NR/GERI-TUSSIN/Guaifenesin/Guiatuss/Iophen-NR/Miltuss EX/Mucinex Children's/Mucus + Chest Congestion/Mucus Relief Children's/Naldecon/Organidin NR/Q-Tussin/Robafen/Robafen Congestion/Robitussin/Robitussin Mucus + Chest Congestion/Scot-Tussin Expectorant/Siltussin DAS/Siltussin Diabetic DAS-Na/Siltussin SA/TUSNEL-EX Oral Sol: 5mL, 10mL, 50mg, 100mg, 200mg, 400mg
Ambi/Amibid LA/Drituss G/Duratuss G/Fenesin/Gua SR/Guaidrine G/Guaifenesin/Guaifenex G/Guaifenex LA/Humibid LA/Liquibid/Mucinex/Muco-Fen/Mucus ER/Mucus Relief/Q-Bid LA/Respa-GF Oral Tab ER: 600mg, 1200mg

Maximum Dosage

2400 mg/day PO.


2400 mg/day PO.


2400 mg/day PO.


12 years: 2400 mg/day PO.
6 to 11 years: 1200 mg/day PO.
2 to 5 years: 600 mg/day PO.
Less than 2 years: Safety and efficacy have not been established.


Safety and efficacy have not been established.

Mechanism Of Action

Guaifenesin loosens and thins phlegm and bronchial secretions to ease expectoration. By reducing the viscosity and adhesiveness of secretions, guaifenesin increases the efficacy of the mucociliary mechanism in removing accumulated secretions from the upper and lower airway. The increased flow of less viscous secretions promotes ciliary action and changes a dry, unproductive cough to one that is more productive and less frequent. Despite its long history of use since the 1950's, the efficacy of guaifenesin has only recently been substantiated. Guaifenesin is used for dry, nonproductive cough when there is the presence of tenacious mucus and/or mucus plugs. The results of a few studies have favored active treatment with guaifenesin over placebo in treating productive cough due to upper respiratory illness (URI).


Guaifenesin is administered orally. The plasma half-life is approximately 1 hour. Guiafenesin is rapidly hydrolyzed (60% within seven hours) and then excreted in the urine, with beta-(2-methoxyphenoxy)-lactic acid as its major urinary metabolite. No unchanged drug was detected in the urine following administration. Renal stones that developed during drug therapy have been documented to contain beta-(2-methoxyphenoxy)-lactic acid and other guaifenesin metabolites. Other pharmacokinetic parameters of guaifenesin are not known.

Oral Route

Guaifenesin is rapidly and well absorbed from the gastrointestinal tract. Extended release products (e.g., Humibid LA) release drug slowly over a period of several hours, allowing for less frequent dosing. The Mucinex brand tablet, a combination immeditate-release/extended-release product, utilizes a patented bilayer delivery system which releases guaifenesin immediately from the first layer and over 12 hours from the second layer. Guaifenesin has a plasma half-life of approximately 1 hour.

Pregnancy And Lactation

Safe use of guaifenesin in pregnancy has not been established and it is not clear if the drug crosses the placenta; guaifenesin should be given to a pregnant woman only if clearly needed. Few studies have been done to evaluate the use of expectorants during pregnancy and thus first trimester use is best avoided. Increased fluids to ease expectoration are usually recommended for first line treatment in the pregnant woman. When the drug must be administered to a pregnant woman, choose guaifenesin product formulations that are alcohol-free.

It is not known if guaifenesin is excreted into breast milk and, according to the manufacturer, it should be given cautiously during breast-feeding since the effects on a nursing infant have not been formally studied. According to experts, however, it is unlikely that with usual maternal guaifenesin doses or amounts in breast milk would harm the nursing infant, especially in an infant over 2 months of age. Increased fluids to ease expectoration are usually recommended for first-line treatment in the lactating individual. If use of guaifenesin is necessary, it is best to avoid the use of guaifenesin products with a high alcohol content; check product ingredients.