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 exami ned. NT-1 (2.5 mg kg(-1) nitroglycerin) decreased systolic blood press ure by 10-15%, while diastolic blood pressure and heart rate were not affected. Coronary blood flow and calculated rate-pressure product wer e decreased. These parameter changes occurred at 30 min after NT-1 app lication and remained constant for 8 h until NT-1 was removed. After a dministration of NT-1 in combination with nifedipine, systolic blood p ressure was significantly decreased to a greater extent, and heart rat e 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 sug gest that NT-1 may be applicable as a transdermal sustained release me dication, and show that in combination with nifedipine, NT-1 can induc e a large increase in coronary blood flow without further increasing r ate-pressure product.