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Expectorants are drugs that loosen and clear mucus and phlegm from the respiratory tract.


The drug described here, guaifenesin, is a common ingredient in cough medicines. It is classified as an expectorant, a medicine that helps clear mucus and other secretions from the respiratory tract. However, some debate exists about how effectively guaifenesin does this. In addition, some cough medicines contain other ingredients that may cancel out guaifenesin's effects. Cough suppressants such as codeine, for example, work against guaifenesin because they discourage coughing up the secretions that the expectorant loosens.
There are other ways to loosen and clear the respiratory secretions associated with colds. These include using a humidifier and drinking six to eight glasses of water a day.


Guaifenesin is an ingredient in many cough medicines, such as the brand names Anti-Tuss, Dristan Cold & Cough, Guaifed, GuaiCough, and some Robitussin products. Some products that contain guaifenesin are available only with a physician's prescription; others can be bought without a prescription. They come in several forms, including capsules, tablets, and liquids.

Recommended dosage

Adults and children 12 and over

200-400 mg every four hours. No more than 2,400 mg in 24 hours.

Children 6-11

100-200 mg every four hours. No more than 1,200 mg in 24 hours.

Children 2-5

50-100 mg every four hours. No more than 600 mg in 24 hours.

Children under two

Not recommended.


Do not take more than the recommended daily dosage of guaifenesin.
Guaifenesin is not meant to be used for coughs associated with asthma, emphysema, chronic bronchitis, or smoking. It also should not be used for coughs that are producing a large amount of mucus.
A lingering cough could be a sign of a serious medical condition. Coughs that last more than seven days or are associated with fever, rash, sore throat, or lasting headache should have medical attention. Call a physician as soon as possible.
Some studies suggest that guaifenesin causes birth defects. Women who are pregnant or plan to become pregnant should check with their physicians before using any products that contain guaifenesin. Whether guaifenesin passes into breast milk is not known, but no ill effects have been reported in nursing babies whose mothers used guaifenesin.

Side effects

Side effects are rare, but may include vomiting, diarrhea, stomach upset, headache, skin rash, and hives.


Guaifenesin is not known to interact with any foods or other drugs. However, cough medicines that contain guaifenesin may contain other ingredients that do interact with foods or drugs. Check with a physician or pharmacist for details about specific products.

Key terms

Asthma — A disease in which the air passages of the lungs become inflamed and narrowed.
Bronchitis — Inflammation of the air passages of the lungs.
Chronic — A word used to describe a long-lasting condition. Chronic conditions often develop gradually and involve slow changes.
Cough suppressant — Medicine that stops or prevents coughing.
Emphysema — An irreversible lung disease in which breathing becomes increasingly difficult.
Mucus — Thick fluid produced by the moist membranes that line many body cavities and structures.
Phlegm — Thick mucus produced in the air passages.
Respiratory tract — The air passages from the nose into the lungs.
Secretion — A substance, such as saliva or mucus, that is produced and given off by a cell or a gland.
References in periodicals archive ?
The reduction in vitro in viscosity of mucoprotein solutions by a new mucolytic agent, N-acetyl-L-cysteine.
A new study by De Rosa and colleagues, published in the European Journal of Clinical Investigation, investigated the use of N-acetylcysteine (NAC), a mucolytic agent used to reduce the viscosity of mucus and to build up glutathione levels in HIV-positive patients.
Use of mucolytic agent may increase the yield of positive culture to 96%.
NAC also functions as a mucolytic agent when given by inhalation.
Iodine has a plethora of other therapeutic actions and can be used as an antibacterial, anticancer, antiparasitic, antiviral, or mucolytic agent.
Joint fluid, decontaminated with Sputagest 50 mucolytic agent (Remel, Lenexa, KS), grew mycobacteria after 7 days of incubation at 36[degrees]C with Middlebrook 7H12 TB media (Becton Dickinson, Sparks, MD) and Lowenstein-Jensen agar.
Some patients with HIV sinusitis might benefit from a mucolytic agent such as guaifenesin, owing to the thick and tenacious nature of their mucus.
Phytobezoars, on the other hand, can be treated medically with motility stimulating, enzymatic, pro-kinetic, and mucolytic agents as well as endoscopically by fragmenting them with snares and forceps.
Mucolytic agents have an important role in managing COPD exacerbations because increased mucus secretions causes coughing and the mucus plugs can obstruct airways and lead to increased death.