Treatment of cluster headache: clinical trials, design and results

The spontaneous capricious course of cluster headache may give rise to some problems when treatment is being evaluated. This is one of several explanations for there being so few well-designed, randomized, double-blind clinical trials in cluster headache. The standard treatment of acute attacks of cluster headache is inhalation of 100% oxygen. In the prophylaxis of episodic cluster headache, ergotamine, verapamil, lithium, serotonin, inhibitors and steroids are used. In chronic cluster, lithium is the drug of choice, but verapamil may also be tried. Recently, hyperbaric oxygen has been shown to immediately abort acute attacks, and it seems that it may also be useful in the prophylactic treatment. The introduction of the novel 5HT1 agonist sumatriptan as a symptomatic relief of cluster attacks represents further significant progress. Two randomized, double-blind, placebo-controlled, cross-over trials have shown sumatriptan 6 mg sc to be a rapid, effective and well-tolerated acute treatment for cluster headache attacks. Within 15 min of treatment, 74% of attacks on sumatriptan responded compared to 26% of placebo-treated attacks. Functional disability was also significantly improved. Increasing the dose to 12 mg did not offer significantly greater relief compared to sumatriptan 6 mg, but was associated with an increased incidence of adverse events. Interim analysis of 3 months of data from a recent multinational open trial comprising, 138 patients having treated 6353 attacks with subcutaneous sumatriptan 6 mg revealed a headache relief in 96% of attacks treated. There was no evidence of an increased incidence of adverse events with frequent use of sumatriptan. No tachyphylaxis was seen over the 3 months, suggesting that sumatriptan is effective and well tolerated also in long-term acute treatment for cluster headache.