Most Cough Medicines Don't Do a Thing -- Here's What Works

Most Cough Medicines Don't Do a Thing -- Here's What Works

By TARA PARKER-POPE
Staff Reporter of THE WALL STREET JOURNAL
January 10, 2006

Every year consumers spend billions on cough medicines, but a new report from the nation's top chest doctors says many of them don't work.

The finding was issued by the American College of Chest Physicians as part of its comprehensive guidelines for dealing with various forms of cough. The doctors group reviewed numerous medical studies evaluating cough preparations and concluded that many of the key ingredients in popular cough and cold medications simply aren't effective in quieting coughs caused by the common cold.

But there was good news as well. The group concluded that the ingredients found in certain older allergy medications and pain relievers are actually far more effective against cough, even though they aren't marketed as cough treatments.

Among other findings, the group concluded that the drug guaifenesin -- an expectorant found in popular brands such as Wyeth's Robitussin and Mucinex from Adams Respiratory Therapeutics in Chester, N.J. -- is ineffective in curbing cough caused by the common cold. The drug is supposed to work by thinning the mucus and making it easier to cough up phlegm. But among four studies evaluating guaifenesin compared with a placebo, two studies showed benefit while two showed no improvement. As a result, the panel concluded there isn't enough evidence to support its use to help cough caused by colds.

The panel also considered two popular cough suppressants, codeine and dextromethorphan, which potentially work by quieting the brain's cough center. Although the drugs may be effective against certain types of coughs -- like those associated with cancer -- these drugs don't work against cough due to colds, says Richard Irwin, professor of medicine at University of Massachusetts Medical School in Worcester, Mass., and editor in chief of the ACCP guidelines. In addition, codeine, even in large doses, hasn't been shown to work on cough due to a common cold, says Dr. Irwin.

Wyeth, the maker of the Robitussin line of cough products, which contain guaifenesin and dextromethorphan, says the group's findings run counter to conclusions by the Food and Drug Administration, which found the ingredients to be both safe and effective during a sweeping review of over-the-counter cough and cold remedies more than a decade ago.

"Robitussin has a long history of being sold, and it has a loyal following of customers," says Francis Sullivan, spokesman for the Wyeth Consumer Healthcare unit in Madison, N.J. "We believe that if the product didn't work these customers wouldn't purchase it."

Dr. Irwin says one explanation for the popularity of cough remedies might be the placebo effect -- which is a positive reaction to an inactive substance that the patient believes will work. In cough studies, the placebo effect has been shown to be as high as 40%.

The Chest panel also concluded that products containing zinc also are ineffective against cough due to colds. The herb echinacea has also been shown to be ineffective against cough.

The panel did conclude that some older antihistamines -- the kind that make you drowsy -- can be effective against cough caused by a cold. The medication in the drugs that makes you sleepy is the same drug that dries up the secretions in the back of the throat that can contribute to cough. The drugs may also act on the brain center to suppress cough, although how they work isn't entirely clear.

Drugs that may help quiet a cough due to cold include diphenhydramine, the active ingredient in Benadryl, dexbrompheniramine, an active ingredient in Drixoral, and chlorpheniramine, the active ingredient in Chlortrimeton.

Drugs like Benadryl and other drowsiness-inducing antihistamines aren't for everyone. The drowsy side effect is a real concern for people who must operate equipment or drive, and men with prostate problems may suffer additional side effects, such as difficulty urinating. "People think all antihistamines are equal, but it's not the case," says Dr. Irwin.

Many newer antihistamines have been altered so as to not make patients drowsy -- a major selling point of the drugs. However, the change that makes them nondrowsy also may render them ineffective against cough, notes Dr. Irwin.

Pain relievers called nonsteroidal anti-inflammatory drugs, such as naproxen, the active ingredient in Aleve, also may help patients with cough caused by cold. In studies naproxen has been shown to decrease the severity and frequency of cough. As a result, doctors believe it's likely similar drugs, such as the ibuprofen found in Advil, might also help relieve cold-related cough. The drugs may cause stomach upset or increase risk for serious gastrointestinal problems. One study has also linked naproxen with a higher risk for heart problems, although the finding remains controversial.

While the guidelines generally dispute the notion that most over-the-counter cough remedies help coughs due to colds, there is some evidence that drugs like dextromethorphan might help other types of coughs, such as those due to bronchitis.

As a result, it's important that patients with a nagging cough seek a doctor's advice on how to best treat it. Patients also should read the label, because different versions of the same brand often contain different active ingredients. "There are medicines that do work for just about all conditions that cause cough," says Dr. Irwin. "I would think people would want to take a medicine that's got a pretty good chance of working."

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