Nitroglycerin for ergotism. Experimental studies in vitro and in migraine patients and treatment of an overt case.

Ergotamine was used to induce arterial contraction in vitro (measurement of isometric tension in segments from 3 human temporal arteries) and in vivo (peripheral systolic blood pressure measured by strain gauge plethysmography in 5 migrainous patients). In both these models of ergotism, the directly acting vasodilator nitroglycerine (NTG) effectively relieved the ergotamine-induced arterial contractions. A case of ergotism treated successfully with NTG infusion is reported. The diagnosis was based on history and measurement of peripheral systolic blood pressure by strain gauge plethysmography. The latter technique was also used to monitor the response to treatment for 20 h. Blood levels of ergotamine during ergotism were in the therapeutic range. Possible explanations for this finding are discussed.