Clevidipine

Clevidipine is a dihydropyridine L-type calcium channel blocker. L-type calcium channels mediate the influx of calcium during depolarization in arterial smooth muscle. Experiments in anesthetized rats and dogs show that clevidipine reduces mean arterial blood pressure by decreasing systemic vascular resistance. Clevidipine does not reduce cardiac filling pressure (pre-load), confirming lack of effects on the venous capacitance vessels.

Clevidipine is titrated to the desired reduction in blood pressure. The effect of clevidipine appears to plateau at approximately 25% of baseline systolic pressure. The infusion rate for which half the maximal effect is observed is approximately 10 mg/hour.

Onset of Effect: In the perioperative patient population, clevidipine produces a 4-5% reduction in systolic blood pressure within 2-4 minutes after starting a 0.4 mcg/kg/min infusion (approximately 1-2 mg/hr).

Maintenance of Effect: In studies up to 72 hours of continuous infusion, there was no evidence of tolerance or hysteresis.

Offset of Effect: In most patients, full recovery of blood pressure is achieved in 5-15 minutes after the infusion is stopped.

In studies up to 72 hours of continuous infusion, in patients that were not transitioned to other antihypertensive therapies, there was some evidence of rebound hypertension following clevidipine discontinuation.

Hemodynamics: clevidipine causes a dose-dependent decrease in systemic vascular resistance.

Heart Rate: An increase in heart rate is a normal response to vasodilation and decrease in blood pressure; in some patients these increases in heart rate may be pronounced.

Electrophysiologic Effects: In healthy volunteers, clevidipine or its major carboxylic acid metabolite, at therapeutic and supratherapeutic concentrations (approximately 2.8 times steady-state), did not prolong cardiac repolarization.

Clevidipine is rapidly distributed and metabolized resulting in a very short half life. The arterial blood concentration of clevidipine declines in a multi-phasic pattern following termination of the infusion. The initial phase half-life is approximately 1 minute, and accounts for 85-90% of clevidipine elimination. The terminal half-life is approximately 15 minutes.

Distribution

Clevidipine is >99.5% bound to proteins in plasma at 37°C. The steady-state volume of distribution was determined to be 0.17 L/kg in arterial blood.

Metabolism and Elimination

Clevidipine is rapidly metabolized by hydrolysis of the ester linkage, primarily by esterases in the blood and extravascular tissues, making its elimination unlikely to be affected by hepatic or renal dysfunction. The primary metabolites are the carboxylic acid metabolite and formaldehyde formed by hydrolysis of the ester group. The carboxylic acid metabolite is inactive as an antihypertensive. This metabolite is further metabolized by glucuronidation or oxidation to the corresponding pyridine derivative. The clearance of the primary dihydropyridine metabolite is 0.03 L/h/kg and the terminal half-life is approximately 9 hours.

In vitro studies show that clevidipine and its metabolite at the concentrations achieved in clinical practice will not inhibit or induce any CYP enzyme.

In a clinical study with radiolabeled clevidipine, 83% of the drug was excreted in urine and feces. The major fraction, 63-74% is excreted in the urine, 7-22% in the feces. More than 90% of the recovered radioactivity is excreted within the first 72 hours of collection.