PMID: 2501598Jun 1, 1989Paper

Circulatory counter-regulations induced by continuous administration of nitroglycerin

Methods and Findings in Experimental and Clinical Pharmacology
P R ImhofF Burkart

Abstract

In a placebo-controlled, double-blind, cross-over study in seven healthy volunteers, continuous transdermal administration of nitroglycerin over 48 h by means of Nitroderm TTS 10 evoked counter-regulations that interfered with the nitrate effects. These counter-regulations comprised an increase in sympathico-adrenal activity, manifested in elevated plasma levels of adrenaline and noradrenaline, and an internal hemodilution, readily perceptible from the decrease in the hematocrit readings. As a result, several of the circulatory effects of nitroglycerin were no longer in evidence, or much weaker on the second day of the study. The effects concerned were the reduction of systolic and diastolic blood pressure, the increase in heart rate, the prolongation of PEPc, and shortening of LVETc, and the change in digital-pulse morphology (increase in the a/b quotient). On the other hand, the increase in venous distensibility and the decrease in hematocrit were unaltered throughout the observation period. The attenuation of the action of nitroglycerin noticeable 24 h after application of the patches is, therefore, not indicative of any loss of effect of the substance per se, but due to the circulatory counter-regulations, which were largel...Continue Reading

Related Concepts

Related Feeds

Antianginal Drugs: Mechanisms of Action

Antianginal drugs, including nitrates, beta-blockers, and calcium channel blockers, are used in the treatment of angina pectoris. Here is the latest research on their use and their mechanism of action.