Worst Pills, Best Pills

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Drug Profile

Do NOT stop taking this or any drug without the advice of your physician. Some drugs can cause severe adverse effects when they are stopped suddenly.

Do Not Use [what does this mean?]
Generic drug name: guaifenesin and dextromethorphan (gwye FEN e sin and dex tro meth OR fan)
Brand name(s): MUCINEX DM, ROBITUSSIN COUGH+CHEST CONGESTION DM, ROBITUSSIN-DM
GENERIC: not available FAMILY: Combination antihistamine, decongestants and/or cough preparations
Find the drug label by searching at DailyMed.

Alternative Treatment [top]

See individual drug families.

Facts About This Drug [top]

In general, combination drugs present extra risks because the extra ingredients usually will not add any benefit and instead can increase the risk of side effects. Further, combination drugs will invariably cost much more than the single ingredient alone. They represent a “shotgun” approach to multiple symptoms of colds, coughs and allergies that rarely occur in the combination that is suggested by the ingredients in these products. (For detailed information about an individual ingredient in...

In general, combination drugs present extra risks because the extra ingredients usually will not add any benefit and instead can increase the risk of side effects. Further, combination drugs will invariably cost much more than the single ingredient alone. They represent a “shotgun” approach to multiple symptoms of colds, coughs and allergies that rarely occur in the combination that is suggested by the ingredients in these products. (For detailed information about an individual ingredient in one of these combination drugs, click on it in the following list: dextromethorphan, guaifenesin.)

Guaifenesin (MUCINEX, ROBITUSSIN) lacks adequate evidence of effectiveness to be recommended as part of the treatment for coughs or colds. Coughs associated with upper respiratory infections are best not treated with drugs. Alternative treatments for a stuffy nose from a cold include nasal spray or drops for a stuffed nose from a cold (see oxymetazoline) and a single-ingredient oral antihistamine for allergies (see chlorpheniramine). It is best not to use drugs to treat coughs associated with upper respiratory infections.

We have classified dextromethorphan as DO NOT USE because of a study published in 2004 in Pediatrics.[1]The study concluded that dextromethorphan was not better than a placebo in providing nighttime symptomatic relief for children with a cough and sleep difficulty as a result of upper respiratory tract infection.

Dextromethorphan has not been found to be effective in clinical trials, and growing evidence suggests that the drug can have significant toxic effects. These toxic effects were found to be particularly associated with the combined use of dextromethorphan and some other medications.

Serotonin syndrome can occur when dextromethorphan is taken together with other drugs that increase levels of serotonin (a chemical in the body).[2]

See the June 2010 issue of Worst Pills, Best Pills News for symptoms of serotonin syndrome and for the list of drugs that can interact with dextromethorphan to increase serotonin levels.

last reviewed February 28, 2021