Calcium Antagonists for Perioperative Blood Pressure Control

Abstract

Calcium entry blockers constitute three major classes of pharmacologic agents: phenylalkylamines (eg, verapa mil), benzothiazepines (eg, diltiazem), and dihydropyri dines (eg, nifedipine). The effectiveness of all types of calcium channel blockers in the prevention and treat ment of coronary artery disease as well as chronic and acute hypertension is undisputable. Their beneficial clinical effects may be due to peripheral and coronary vasodilatation, resulting in reduction in myocardial oxy gen consumption, and an increase in myocardial oxy gen supply in addition to their antispasmodic effect and the ability to prevent intracellular calcium overload. For the management of perioperative hypertension develop ing in patients undergoing cardiac or noncardiac sur gery, the dihydropyridines appear to be especially suit able. Intravenous (IV) formulations of nifedipine, nicardipine, and isradipine have been successfully used in this setting. At the present time, nicardipine is the most widely used IV dihydropyridine. This is due to its potent afterload-reducing activity and relatively short duration of action, although its effect may increase the longer the drug is being infused. The ideal drug for perioperative blood pressure control should be one with the pharmacodynamic profile of the vascular selec tive dihydropyridines, but with an ultrashort duration of action.

Pharmacodynamic, Pharmacokinetic and Clinical Effects of Clevidipine, an Ultrashort‐Acting Calcium Antagonist for Rapid Blood Pressure Control

“…The most commonly used drugs for controlling perioperative hypertension are nitroglycerin (GTN), sodium nitroprusside (SNP), â-adrenoceptor and calcium antagonists (51,52). Both GTN and SNP have a pharmacokinetic profile that allows rapid titration to the desired blood pressure level (40). However, these drugs are non-selective vasodilators, they dilate both arteriolar resistance as well as venous capacitance vessels (37,40).…”

“…Both GTN and SNP have a pharmacokinetic profile that allows rapid titration to the desired blood pressure level (40). However, these drugs are non-selective vasodilators, they dilate both arteriolar resistance as well as venous capacitance vessels (37,40). The latter effect may compromise venous return and thereby reduce cardiac output (CO) (24).…”

“…In addition, SNP may induce side effects such as rebound hypertension at the cessation of infusion, coronary steal and potentially cyanide toxicity (24). Moreover, drug tolerance is a common concern with GTN or SNP (24,40).…”

“…However, â-adrenoceptor antagonists decrease blood pressure at least partly by reducing CO. They do not affect primarily increased SVR, the most common reason for elevated blood pressure during cardiac surgery (35,37,40). A potential drawback of reducing CO is impaired organ perfusion.…”

“…Among calcium antagonists, dihydropyridines are highly vasoselective; they dilate precapillary resistance vessels without depressing cardiac contractility (40,51). Calcium antagonists protect against organ damage induced by ischemia/reperfusion (40,42), e.g., of the kidney, intestines and heart. The functions of these organs are sometimes jeopardized during major cardiac surgery.…”