[A transdermal intermittent-release nitroglycerin system. Hemodynamic studies after acute and subchronic use]

The efficacy of a transdermal intermittent-release nitroglycerin system was investigated in a randomized double-blind trial on 24 patients (18 males and six females; median age 57.5 years [range 41-68]) with angiographically proven and haemodynamically significant coronary heart disease. Twelve patients had one plaster, containing 10 mg nitroglycerin, daily for eight days, the other twelve also had one plaster, but without drug, daily for eight days. Resting and exercise haemodynamics were measured on the first day, immediately before and two hours after application of the plaster, on the eighth day 24 hours after the last but one plaster application, and two hours after the last plaster. The mean pulmonary artery pressure, two hours after first plaster application, had dropped at rest from 18.6 to 13.3 mm Hg (29%; P less than 0.001) and after exercise from 43.9 to 34 mm Hg (23%; P less than 0.001). After eight days, 24 hours after application of the penultimate plaster, there was no significant haemodynamic change. Renewed plaster application, however, caused significant haemodynamic changes similar to those on the first day of the study. It is concluded from these findings that this intermittent-release system can achieve long-term results without development of tolerance.