Chronic Cough Responds to Epilepsy Drug, Study Finds
TUESDAY, Aug. 28 -- A drug commonly used to control epileptic seizures and pain, gabapentin, also appears to ease hard-to-treat chronic coughs, a new study says.
Chronic cough affects 11 percent to 16 percent of the population, the researchers report. The exact cause is unknown, but it might relate to a malfunction in a part of the brain that causes coughing. Gabapentin works by suppressing that "cough center," they said.
"It is effective and well-tolerated, and may provide significant relief and respite from such a physically and psychologically disabling condition," said lead researcher Nicole Ryan, a clinical research scientist at the University of Newcastle in Australia. "Gabapentin is a real treatment option for people with refractory chronic cough, especially for those with features of central sensitization."
People with this kind of cough feel the need to cough when there is no cough stimulus present. It's thought that neurons in the central nervous system fire off unnecessarily.
The report is published online Aug. 28 in The Lancet.
For the study, Ryan's team evaluated 52 people with chronic cough that had not responded to other treatments to. All had had their cough two months or longer and were randomly assigned to take gabapentin or placebo.
Over 10 weeks, the researchers measured the effect of treatment using a questionnaire that scores the physical, social and psychological impact of the cough. They also assessed the frequency and severity of the cough.
People taking gabapentin had a significant improvement in quality of life, cough severity and frequency of cough compared with those taking placebo, Ryan's group found.
After eight weeks, nearly three-quarters of people taking gabapentin reported improved cough scores, compared with 46 percent of those taking placebo.
The benefit of gabapentin, however, did not continue once the drug was stopped, the researchers noted.
Some patients taking gabapentin had side effects, most commonly nausea and fatigue, which were eliminated by lowering the dose, the researchers said.
"This study has opened up the door for further investigation of gabapentin," Ryan said. "The addition of gabapentin to chronic cough standard practice guidelines should be considered, although replication studies are necessary before this happens."
Dr. Len Horovitz, an internist and pulmonologist at Lenox Hill Hospital in New York City, isn't convinced a lot of people suffer with unexplained chronic cough.
"In almost every instance, you find the cause of the cough and treat it and it disappears," he said. "In over 30 years of practice I haven't seen 11 to 16 percent of patients with central sensitization as a reason for chronic cough," not even one.
If there were such a case, it's possible that gabapentin could have a role in treating it since it suppresses the brain area that controls cough, he acknowledged.
But the most common cause of chronic cough is undetected or under-treated sinusitis, Horovitz said.
In this study, he noted, many of those taking placebo also showed improvement, indicating their cough might be psychologically based.
Horovitz added that serious side effects, such as hallucinations, can occur with gabapentin, making the drug intolerable for some patients.
"So before reaching for gabapentin, I would continue a search and try to pin down a diagnosis," Horovitz said.
For more on cough, visit the U.S. National Library of Medicine.
Posted: August 2012