Nearly one in five adult women experience migraine headaches, compared with one in twenty adult men. Menstrual migraine is defined as headache that occurs regularly in close relationship to the onset of menstruation (between two days prior to and during the first three days of bleeding). Until recently, studies documenting migraine and menstruation have included small numbers of women over few cycles, often combining data from women using hormonal treatments with those who were not. Also, data has not been collected regarding the difference between menstrual versus non-menstrual migraine attacks within the same woman, rather than comparing attacks within a total population.
Researchers from the City of London Migraine Clinic analyzed diary data from 155 women patients. All of the women tracked at least two cycles, with nearly half of the patients keeping diary cards over the course of four or more menstrual cycles.
Diary card analysis showed that in the five days preceding menstruation, women were 25 percent more likely to have migraine; migraine was 71 percent more likely to occur during the two days before menstruation. The chance of migraine was more than twofold on the first day of menstruation and within five days afterward.
Severe attacks were more likely to occur during the pre-menstruation and post-menstruation intervals compared to all other times of a woman's cycle. Women were almost five times more likely to have a migraine associated with vomiting on or during days one to three of menstruation.
"Our study supports new International Headache Society diagnostic criteria regarding pure menstrual migraine and menstrually related migraine," concluded study author Anne MacGregor, MFFP, of the City of London Migraine Clinic and St. Bartholomew's Hospital, London.
Meanwhile, researchers led by Stephen D. Silberstein, MD, FACP, of Thomas Jefferson University in Philadelphia, studied the use of frovatriptan in the prevention of menstrually associated migraines.
"Women have long reported menstrually related migraines as prolonged and difficult to manage with conventional therapies," said Silberstein. Frovatriptan, indicated for acute treatment of migraine, has a long therapeutic life and is generally well tolerated, making it a natural agent to study as a preventive therapy.
This double-blind, placebo-controlled, three-way crossover study involved 443 patients from 36 U.S. centers. Patients were randomly assigned to placebo, 2.5 mg frovatriptan once daily and 2.5 mg frovatriptan twice daily for each of three menstrual cycles. The six-day treatment started two days before the anticipated start of menstrually associated migraine (previously determined by each participant).
Use of frovatriptan reduced the occurrence of migraine, with the incidence of migraine using placebo at 67 percent, with once-daily frovatriptan at 52 percent, and twice-daily frovatriptan at 41 percent. Both frovatriptan regimens also reduced migraine severity, duration and the use of additional migraine medication.
"More than half of patients who used frovatriptan 2.5 mg twice daily had no menstruation-associated migraine," noted Silberstein. Study findings are consistent with the long duration of action of frovatriptan that has been observed in studies of acute treatment of migraine. He concluded, "The size of our study and the level of statistical significance obtained make our results very robust."
The study by MacGregor et al was supported by grants from the Migraine Action Association and the Golden Charitable Trust. The study by Silberstein et al received support from Vernalis, Ltd., a producer of frovatriptan.
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