Nitroglycerin as a Provocative Agent

IT IS RELATIVELY seldom that the physician has an opportunity to witness an attack of cluster headache (Horton's syndrome). Consequently, the diagnosis generally is based on anamnestic data supplied by the patient. A definite method for provoking an attack would therefore be of value, from both the diagnostic-therapeutic and the pathophysiological aspects, to establish the mechanism of the actual headache. Horton¹⁻³showed that subcutaneous injection of histamine can elicit an attack, and reported positive results in 69% of his cases. The corresponding incidence in Peters' series was 75%.⁴Several authors have, however, doubted the value of the histamine test. Thus, Gardner et al⁵found that a typical attack could be precipitated only in the occasional case, and Friedman and Mikropoulos⁶were not convinced of the specificity or value of the test. Although nitroglycerin has been mentioned as a provocative agent in connection with Horton's syndrome,