Effective treatment of acute migraine is challenging. Intravenous prochlorperazine has documented efficacy in the management of migraine pain. However, the sedative and extrapyramidal effects of prochlorperazine can be distressing. Recently, intravenous sodium valproate has been used successfully in some case series and a single prospective study. Tanen and associates conducted a randomized, controlled, double-blind study to compare the efficacy of sodium valproate and prochlorperazine in the emergent treatment of patients with migraine.

Patients with uncomplicated migraine headaches were randomized to receive 10 mg of prochlorperazine or 500 mg of sodium valproate intravenously. Patients graded their levels of pain, nausea, and sedation on a visual analog scale before treatment and at 15-minute intervals until 60 minutes after treatment.

Both groups demonstrated a significant difference in pain improvement, with patients receiving prochlorperazine showing a significantly greater decrease in pain and nausea scores. There was no difference in sedation scores. At the end of the study, 15 of 19 patients receiving sodium valproate required further treatment, compared with five of the 20 patients in the prochlorperazine group. Two patients in the prochlorperazine group received 25 mg of intravenous diphenhydramine for possible extrapyramidal reactions.

The authors conclude that, compared with prochlorperazine, sodium valproate does not significantly reduce the pain and nausea associated with acute migraine headache. The short follow-up period may have masked effects of sodium valproate that could occur after 60 minutes.