Effect of flordipine on cerebral blood flow

The goal of this study was to determine effects of flordipine (REV 2609), a calcium channel blocker, on blood flow to brain and other organs. Blood flow was measured with microspheres during i.v. infusion of 0.5 to 2.0 mg/kg of flordipine in anesthetized and awake rabbits. In anesthetized rabbits, flordipine (0.5 mg/kg) increased cerebral blood flow by 50%, despite a small decrease in arterial pressure, with no increase in blood flow to skeletal muscle, bowel or kidney. Higher doses of flordipine produced 2- to 3-fold increases in cerebral and myocardial blood flow, marked increases in flow to skeletal muscle, but no increase in blood flow to bowel or kidney. Blood flow remained elevated 1 hr after stopping infusion of flordipine. The increase in cerebral blood flow was not associated with an increase in cerebral oxygen consumption. In awake rabbits, flordipine also produced a dose-related increase in cerebral, myocardial and skeletal muscle flood flow, with no increase in flow to bowel or kidney. Thus, flordipine produces a relatively selective increase in cerebral and myocardial blood flow. The increase in cerebral blood flow is the result of a direct vasodilator effect of flordipine and is not secondary to an increase in cerebral metabolism.