It's a radical idea in a field that hasn't come up with a new active ingredient since the 1950s. Americans spend hundreds of millions of dollars a year on cough syrups for which there is little evidence of effectiveness, at least at doses deemed to be safe. Now, various trials are under way, along with a broad range of preliminary research, on how the nervous system is involved in triggering coughs.
For example, some scientists, including one at Philadelphia's Monell Chemical Senses Center, induce coughs by having people inhale a vapor that contains an extract from chili peppers.
Such research is long overdue, said Paul, who also conducted a 2010 study that found another old cough remedy, vapor rub, to be effective.
"There's not a new drug on the market in 50 years for the most common symptom that there is," Paul said.
The reasons for this pharmaceutical dry spell are many, but a big one is simply that the cough is hard to study, said Brendan Canning, associate professor of medicine at the Johns Hopkins Asthma and Allergy Center.
To start with, the most common type of cough - the one caused by the common cold - eventually goes away by itself.
So, in addition to the usual research practice of determining if a drug's impact is due to pharmacology or to the placebo effect, researchers must also tease out whether patients are simply getting better on their own.
"You have kind of a moving target," said Peter Dicpinigaitis, director of the Montefiore Cough Center and professor at Albert Einstein College of Medicine in New York.
