Effect of Antihypertensive Drugs on Insulin Absorption

Abstract

To examine the effects of antihypertensive drugs on the absorption of subcutaneously injected insulin. Eleven healthy volunteers (group 1) were given 1 mg/kg body wt propranolol three times a day during 48 h and a single dose on the morning of investigation. Seven other healthy volunteers (group 2) were given 10 mg nifedipine 30 min before subcutaneous injection of 10 U 125I-labeled soluble insulin. Absorption was measured by counting radioactivity externally. In both groups, control experiments were conducted under the same conditions without administration of propranolol or nifedipine. Propranolol usage was associated with higher mean percentages of remaining activity (P less than 0.05 by analysis of variance [ANOVA]) than in the control experiment. In the nifedipine experiment, mean percentages were significantly lower compared with the control experiment (P less than 0.02 by ANOVA). The mean decline in activity of all 30-min periods was 6.8 +/- 3.5 vs. 3.6 +/- 3.7% for control versus propranolol (group 1) (P less than 0.05) and 6.3 +/- 1.8 vs. 9.6 +/- 3.2% for control versus nifedipine (group 2) (NS). Antihypertensive drugs can influence insulin absorption. Propranolol (a peripheral vasoconstrictor) decreases insulin absorption, whereas nifedipine (a vasodilatator) increases insulin absorption.