Cardiovascular Effects of NT-1, a New Patch Form of Nitroglycerin, Alone and in Combination with Nifedipine in Conscious Dogs

The cardiovascular effects of NT-1, a new patch form of nitroglycerin, alone and in combination with nifedipine in conscious dogs were examined. NT-1 (2.5 mg kg-1 nitroglycerin) decreased systolic blood pressure by 10-15%, while diastolic blood pressure and heart rate were not affected. Coronary blood flow and calculated rate-pressure product were decreased. These parameter changes occurred at 30 min after NT-1 application and remained constant for 8 h until NT-1 was removed. After administration of NT-1 in combination with nifedipine, systolic blood pressure was significantly decreased to a greater extent, and heart rate and coronary blood flow showed a tendency to increase compared with nifedipine alone. Rate-pressure product was not changed compared with that obtained on administration of nifedipine alone. These results suggest that NT-1 may be applicable as a transdermal sustained release medication, and show that in combination with nifedipine, NT-1 can induce a large increase in coronary blood flow without further increasing rate-pressure product.