Overview of initial clinical studies with intravenous and oral GR43175 in acute migraine.

The novel 5-HT 1-like receptor agonist GR43175 has been evaluated as a treatment for acute migraine in a series of open, dose-ranging and controlled clinical trials. Patients with severe attacks of migraine have attended special pain or headache clinics for treatment and assessment. Given intravenously as a bolus, GR43175 is capable of aborting all migraine symptoms within 10-30 min in over 90% of cases at a dose of 64 micrograms/kg. Characteristic transient and reversible side effects with such a regimen include feelings of heaviness, pressure and occasionally warmth or tingling which can be diminished by extending the duration of drug administration to a short infusion. Initial dose-ranging studies with a dispersible tablet formulation of GR43175 have revealed an efficacy of 70-85% within 2 h with doses of 70-280 mg. Furthermore, tolerability is excellent. These encouraging early results warrant larger-scale controlled studies of GR43175 in acute migraine.