Objectives.—To document the relationship between the use of subcutaneous (SQ) sumatriptan (sum) and a change in frequency pattern of cluster headache (CH) in six patients. To discuss the clinical and pathophysiological implications of this observation in the context of available literature.
Background.—Treatment with SQ sum may cause an increase in attack frequency of CH but data from literature are scant and controversial.
Methods.—Six CH sum-naïve patients (three episodic and three chronic according to the International Headache Society (IHS) criteria) are described.
Results.—All six patients had very fast relief from pain and accompanying symptoms from the drug but they developed an increase in attack frequency soon after using SQ sum. In all patients, the CH returned to its usual frequency within a few days after SQ sum was withdrawn or replaced with other drugs. Five patients were not taking any prophylactic treatment and SQ sum was the only drug prescribed to treat their headache.
Conclusions.—Physicians should recognize the possibility that treatment of CH with SQ sum may be associated with an increased frequency of headache attacks.