Do cough medicines work? Given the billions of dollars that we spend on over-the-counter cough and cold remedies in the U.S. every year, we clearly think they do. But cough experts are not so sure.
“We want to believe these remedies will work because we’re so desperately uncomfortable when we’re sick,” says John E. Heffner, MD, a pulmonologist and immediate past president of the American Thoracic Society. “But clinical trials have not found that cough medicines are any better than a placebo.”
Among experts, doubts about the effectiveness of cough medicines are longstanding. Members of the Consumer Healthcare Products Association ( CHPA), an association that represents most of the makers of nonprescription OTC cough and cold medicines in children, voluntarily modified the labels of OTC cough and cold medicines to state "do not use" in children under 4 years of age.
The reasons: a lack of proven benefit and a small risk of serious side effects.
While cough medicines don’t pose the same risks in adults, a larger question looms. If there’s no good evidence that these drugs work, should anyone be using them? Should we banish those sugary cough syrups from our medicine cabinets? Is it time for us to muddle through the common cold without them?
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.
Popularity of Cough Medicine
But why would these medicines be so popular if there’s no proof that they work? Edelman says it’s simple. “People like them,” he tells WebMD.
* Coughs are the reason for more than 30 million doctor visits every year.
* By some estimates, coughs are the most common medical symptom.
When we’re sick with a cough -- or worse, when our children are sick -- we’re desperate to do something, anything, to relieve it. Knowing that there’s a medicine we can take makes us feel better and more in control.
“It’s really nice to be able to go down a pharmacy aisle and pick up a medicine that says it’s going to help,” Edelman says.
Cough medicines may also seem like they work even if they aren’t. “Most coughs caused by a viral infection get better on their own within a few days,” says Heffner. “But since so many people take cough medicines, they credit the drug for resolving the symptoms.”
Still, you might assume that the government would prevent the sale of medicines that don’t do what they claim to do. But it’s not quite so simple.
“Many of these cough medicines have a long tradition of use behind them,” says Heffner. “If they were being submitted to the FDA for approval today, the evidence might not be good enough to get them approved.” But since they were approved long ago, they are likely to stay that way.
Risks of Cough Medicines Low
The good news about cough medicines is that while they might not work, they’re unlikely to hurt. “If you take a cough medicine as prescribed, the odds of having any problems are pretty small,” Edelman tells WebMD.
Heffner says that the mildly riskier drugs are the decongestants that might be included in some cold and cough medicines. For instance, pseudoephedrine is a stimulant and might be dangerous for people with heart problems or uncontrolled high blood pressure. But the cough medicines themselves should be safe when taken as recommended. The problem is that not everyone takes them that way.
“Virtually all of the problems and side effects from over-the-counter cold and flu medicines are from overdoses,” Edelman says.
You might not think of yourself as the sort of person likely to overdose on a drug. But it may be easier than you expect.
“Often, overdosing is completely accidental,” says Edelman. One cause: people taking different cold and flu remedies at the same time without looking at the ingredients. While the brand names may be different, they may be getting double doses of the same ingredients.
Other times, it’s more deliberate. People may knowingly take doses that are too high. But that’s not necessarily because they’re trying to abuse the drug. They may just be trying to get rid of their cough. One dose doesn’t help, so they try another. Edelman says it’s not uncommon for people to overdose on medicines that don’t work very well precisely because they don’t work very well.
“If a medicine is only marginally effective, people just keep taking more and more, trying to get an effect,” Edelman says.
Do Cough Medicines Have Any Benefits?
Despite the doubts, experts might still recommend these medicines in certain patients. One example is a person who gets a chronic cough after a viral infection. These coughs can be self-perpetuating. Every time you cough, you irritate the airways, and that makes you more likely to cough. It’s like picking a scab. So sometimes, experts recommend cough suppressants in these cases to try to break the cycle of coughing. But Heffner notes that the evidence that they help even in these cases is fairly weak.
* Experts stress that you should never treat a long-lasting cough on your own.
* You should also never use a cough medicine for longer than recommended on the label.
In fact, Heffner says that any cough that lasts longer than five to seven days -- or is accompanied by other symptoms, like a fever or rash -- should be checked out by an expert. You might have something more severe than the common cough that needs expert treatment.
Should You Use Cough Suppressants or Expectorants?
Heffner says that definitive studies of whether cough medicines work are unlikely, since there’s little interest in funding them. So for the foreseeable future, cough medicines will remain on the shelves, whether there’s proof they work or not. Should you use them? That depends.
If you have any health conditions, you should always talk to your doctor before using a cough medicine. And Edelman stresses that you should never use a cough medicine in a child under 6 without talking to his or her pediatrician first.
But for the rest of us, taking a cough medicine for a few days is probably ok.
“Generally, we think these are pretty benign medications in adults,” says Heffner. “When used as prescribed, they should be safe. “ Edelman agrees, and observes that despite the evidence, they do make some people feel better.
“It might just be a placebo effect,” Edelman tells WebMD. “But the placebo effect can be very powerful.”
There is one last thing to consider before deciding whether to use cough medicine: coughing may be good for you.
“In most cases, a cough is actually useful,” says Edelman. “It helps clear out mucus, so you really don’t want to suppress it.”
Of course, that’s probably small comfort when you’re up in the middle of the night with a miserable, hacking cough. A lot of us would really prefer a few teaspoons of cough syrup.
“That drive to get treatment is very strong,” says Heffner, “regardless of whether that treatment really works or not.”