Effect of sumatriptan on cerebral blood flow in migraine headache

Sumatriptan has been reported to increase flow velocities in large cerebral arteries, consistent with a vasoconstrictive effect. We report data from an ongoing study of tissue cerebral blood flow (CBF) in migraine following treatment with sumatriptan. Otherwise healthy patients with a minimum of one migraine headache per month (IHS criteria) were scanned using H₂¹⁵O, and positron emission tomography, within 24 hours of the onset of migraine headache. Patients were re-imaged 0.25, 0.5 and 1 hours following 6 mg SQ sumatriptan, and after a headache free interval of at least 48 hours. CBF in clinical responders (to date, n=4) increased (p=0.04) from a mean (SD) flow of 43.4 (2.9) ml/min/100g prior to treatment, to 51.7 (12.4), 55.1 (11.1), and 52.0 (6.4) ml/min/100g, at 0.25, 0.5 and 1 hour post sumatriptan respectively. CBF was 56.8 (10.8) in the migraine free state. Among non-responders (n=1), CBF decreased from 51.8 to 46.5ml/min/100g CBF is reduced in the headache vs the headache free state. Preliminary evidence suggests that in responders, sumatriptan increases CBF to near headache free levels.