Chronic cluster headache: response to lithium treatment.

A clinical trial of lithium carbonate was undertaken in a group of 20 patients suffering from chronic cluster headache. Blood levels of lithium were determined at regular intervals to monitor the therapeutic dosage. Lithium was found to be an effective prophylactic agent for chronic cluster headache patients. The effectiveness of lithium was evident in less than a week after the beginning of treatment. It is not clear in what way lithium may act on cluster headache.