Nitroglycerin oral spray: evaluation of its coronary artery dilative action by quantitative angiography

Twenty patients were studied angiographically before and after administration of glyceryl trinitrate (NTG) spray at a single oral dose of 0.8 mg in either a hydrosoluble (NTG-h) or liposoluble (NTG-I) solution. The assessment was by a randomized double-blind trial involving quantitative coronary angiography and pharmacological stress testing using ergonovine maleate. The peak effect and duration of NTG-induced coronary dilatation were evaluated in 2 groups of 10 patients each, in whom NTG oral spray was given either under resting conditions (group A) or for the release of ergonovine-increased coronary vasomotor tone (group B). The study demonstrates that the 2 different galenic formulations of NTG spray are equally efficacious in dilating the conductance coronary arteries under both conditions. When NTG-h and NTG-I oral spray were given subsequent to ergonovine-testing, the diameters of extramural coronary arteries are not only reset to their dimensions at baseline but furthermore increase above resting values by 15.1% and 15.5%, respectively. Ergonovine-induced coronary vasoconstriction was released significantly for a period of at least 30 minutes. Both the NTG-h and NTG-I oral spray are potent coronary vasodilators in patients with increased coronary vasomotor tone.