New Way to Gauge Migraine Medications
Heightened skin sensitivity helps determine when they'll work
FRIDAY, Nov. 7, 2003 (HealthDayNews) -- Besides the familiar symptoms of throbbing pain, nausea and sensitivity to light, many migraine patients also suffer from something called cutaneous allodynia, or skin sensitivity.
Routine activities such as combing your hair, shaving and putting on glasses can become excruciatingly painful.
And whether a person has this condition can apparently predict how they respond to triptans, a major class of migraine drugs, claims new research in the Nov. 7 online edition of the Annals of Neurology.
"It explains to us why triptans work when they do and why they don't," says study author Rami Burstein, an associate professor of neurology at Harvard Medical School. The study was partially funded by the National Institutes of Health and GlaxoSmithKline, which first developed triptans.
This information could also make the treatment of migraines much more predictable and less of a hit-or-miss affair.
Migraine headaches are still somewhat of a mystery. No one knows why certain people get migraines and others don't. Even if a person is susceptible to migraines and has a particular trigger, it's not clear why that trigger only initiates a migraine some of the time.
Triptans, which debuted in the early 1990s, are also perplexing, sometimes working in one person and, another time, failing to work in the same person.
To try to unravel these mysteries, Burstein and his colleagues looked at the effect of triptans on 34 migraine attacks that involved allodynia and 27 attacks that did not.
In the final analysis, triptans relieved pain in most of the patients without skin sensitivities, regardless of when treatment was initiated.
In those with the sensitivity, the drugs worked best when they were administered early.
The findings have prompted Burstein to suggest a new classification for treating migraines. "I can predict now with about 90 percent accuracy which migraine attacks would be terminated by triptan before I even treat," he says. "Patients with migraine with allodynia should be differentiated from those who don't."
An accompanying rat study, also led by Burstein, sheds light on the neurological mechanisms behind this phenomenon.
At first, migraine symptoms involve nerves that are outside the brain. "As time goes on and the migraine intensifies and grows, that pain generation changes from outside the brain to inside the brain and it ultimately can create allodynia," explains Dr. Roger Cady, director of the Headache Care Center in Springfield, Mo., and a member of the board of directors of the National Headache Foundation.
"Once the migraine changes from the outside nerves to the inside nerves, the effectiveness of triptans drops off dramatically. The reason is that those drugs work primarily on those nerves outside of the brain," Cady says.
For doctors and migraine sufferers, the clear message is to act early.
"Don't wait for pain to become disabling," Cady says. "The reality is there is no penalty for early treatment. If you are someone whose headaches involve allodynia, it is critical that you treat early, otherwise you are not going to get relief."
Dr. Ellen Drexler, director of the Headache Center at Maimonides Medical Center in New York City, says the new research "reinforces the idea that it's important to take migraine medications early in the course of the headache."
And while the new findings appear to have immediate application for people who suffer from migraines, they also hold out hope for people whose headaches cannot be helped by triptans.
"Burstein is also opening up a whole new arena of potential targets for future therapy [meaning the nerves inside the brain]," Cady says. "Triptans are very good drugs, but not everybody and not every headache responds. This could help people with acute headaches. It may also have good implications for preventing headaches."
For more on migraines, visit the National Headache Foundation or the National Institute of Neurological Disorders and Stroke.