Cough Medicine: The Evidence

Over the years, a number of studies have found little evidence that cough medicines work.

• Most recently, in 2006, the American College of Chest Physicians (ACCP) surveyed a number of cough medicine studies from the last few decades. These medicines include drugs to suppress the cough, like dextromethorphan (DM), as well as expectorants like guaifenesin, which are supposed to loosen up mucus in the airways so you can cough it up. The AACP found no evidence that these medicines help people with run-of-the-mill coughs caused by viruses.
• A 2004 review of studies had a similar conclusion. That study found that almost 60% of the studies showed no benefit to cough medicines over a placebo.

Of course, it’s important to understand that these studies have not proven that cough medicines don’t work. Rather, they’ve just shown that there isn’t good evidence that they do. It’s possible that further studies could show that they help.

The ACCP study did find one combination of drugs that did work. When combined with a decongestant, the older antihistamine, brompheniramine, eased coughs caused by colds and allergies.

The catch is that brompheniramine, like other first generation antihistamines, is a sedative. So it’s not something you could take before school or work. “The sedative effect is actually what might be helping with the cough,” says Norman Edelman, MD, chief medical officer at the American Lung Association.