MONDAY, Dec. 22, 2003 (HealthDayNews) -- The epilepsy drug gabapentin, when taken daily, relieves pain in a third of patients with chronic daily headache, Australian researchers report.
Chronic daily headache is a condition defined as headaches occurring on at least 15 days every month and lasting for more than four hours, says lead researcher Dr. Roy G. Beran, of the department of neurology at Liverpool Hospital in New South Wales. "Chronic daily headaches include migraines, chronic tension headaches or headaches from other causes," he says.
"Gabapentin proved to be effective in the treatment of chronic daily headache," Beran says.
The researchers conducted a randomized, placebo-controlled study in which patients were selected to receive gabapentin or a placebo for six weeks. After the first six weeks, there was a one-week period when no treatment was given, and then the groups switched treatment for a second six-week period.
In the trial, conducted by the Australian Gabapentin Chronic Daily Headache Group, patients receiving gabapentin were given 2,400 milligrams a day. That is the maximum approved dose in Australia for treating people with epilepsy, Beran notes.
Of the 133 men and women in the study, data was available for 95, according to the report in the Dec. 23 issue of Neurology.
Beran's team found a third of the people in the study stopped having daily chronic headache while receiving gabapentin. "So it worked over the full spectrum of headaches," he says.
"Those who had a response did brilliantly," Beran says. However, he adds, "there was a significant number who did not have a response."
Beran points out that in Australia, as in the United States, gabapentin is approved only for the treatment of epilepsy. However, it is being used "off license" as a painkiller and to treat depression, mania and anxiety, he says.
Beran believes that with a physician's approval, gabapentin should be used to treat chronic daily headache in patients where all other treatments have failed.
He also speculates that higher doses of gabapentin may be even more effective and may improve the response among patients who do not respond to the dosage used in his current study.
"Gabapentin is one of the safest products ever made," Beran says. He believes it can be given in doses of up to 5 grams per day without harmful effects. "The upper limits of doses of gabapentin for epilepsy have not been defined," he says.
For people with chronic daily headache, Beran stresses "there is hope out there -- don't give up. Our study clearly shows that there is benefit to using gabapentin in the treatment of chronic daily headache."
Dr. Stephen D. Silberstein, a professor of neurology and director of the Jefferson Headache Center at Thomas Jefferson University in Philadelphia, calls the Australian finding interesting but not very persuasive.
"In my experience, gabapentin is not a very successful medication for headache disorders," says Silberstein, who wrote an accompanying editorial that appears in the journal.
Silberstein finds fault with the new study because it didn't differentiate between the types of headaches and how those headaches reacted to gabapentin. In addition, the overall beneficial effect of the drug was not very great, he says.
Silberstein agrees that very high doses of gabapentin would probably have a better effect. However, those higher doses could lead to unwanted side effects seen at high doses, such as lethargy, balance problems and cognitive changes associated with other epilepsy drugs.
For those reasons, Silberstein doesn't believe gabapentin will be useful in treating chronic daily headache. "There are other, newer drugs now in clinical trial that have as much as an 80 percent success rate with chronic every day headache," he says.
More information
To learn more about headaches, visit the American Headache Society or the National Library of Medicine.
