Drug-resistant cluster headache responding to gabapentin: a pilot study.

Prompted by the results of gabaergic drugs, such as valproate and topiramate, we performed this pilot study to assess the effect of gabapentin in cluster headache. Eight patients suffering from episodic cluster headache and four suffering from chronic cluster headache were studied. All of them had failed to respond to traditional prophylactic drugs. The design of the study was an open trial. The main parameter for effectiveness was the number of daily attacks. Gabapentin was given at the daily dosage of 900 mg. All patients were pain free after a maximum of 8 days after starting therapy, with a bout duration thus reduced to 16-40% of the average previous bouts (only applies to episodic cluster patients). We hypothesize that the gabaergic action of gabapentin, perhaps combined with other mechanisms, such as calcium channel blockade, may be responsible for its remarkable effects on cluster headache.