Adrenal catecholamine releases during hypotension with continuous administration of calcium entry blockers and nitroglycerin

: We investigated the effect of nicardipine and diltiazem on adrenal catecholamine releases, and compared it with the effect of nitroglycerin in dogs. A 35% reduction in mean arterial pressure was achieved and maintained for 45 minutes. The dogs were observed until 60 minutes after the discontinuation of drug infusions. Adrenal catecholamine releases increased during hypotension with continuous administration of nicardipine, diltiazem and nitroglycerin, but they showed no significant differences between each drug. There was no more increase in adrenal catecholamine releases in spite of additional nicardipine administration. These results suggest that Ca2+ antagonist such as nicardipine directly inhibits the catecholamine releases from the adrenal glands.