Circulatory effects of nitroglycerin ointment (Nitrong) with special reference to venous distensibility.

Nitroglycerin ointment (Nitrong 2%, 5 cm) and an identical placebo ointment were tested in a double-blind crossover study in five healthy volunteers to determine its influence on heart rate, blood pressure, and venous distensibility during supine rest and at 45 degrees tilt. Two hours after administration, a significantly higher venous distensibility was observed with the active ointment than with placebo. There were insignificant changes in heart rate and blood pressure. Three of the five subjects experienced headache for 6 h or more after active ointment.