Applied Pharmacology, Janssen Pharmaceutica

Abstract

1) Flunarizine (0.3 and 1 mg/kg, i.v.) and papaverine (1 mg/kg, i.v.) caused significant increases in cerebral blood flow and decreases in cerebral vascular resistance with concomitant increases in cerebrospinal fluid pressure, in spite of decreases in systemic blood pressure. The durations of these effects by flunarizine were longer than those by papaverine. 2) Heart rate increased markedly with papaverine, while it decreased with flunarizine only at a dose of 1 mg/kg, i.v. Central venous pressure increased slightly and temporarily with flunarizine, but it was not changed with papaverine. 3) Cerebral arteriovenous oxygen difference decreased with either of the drugs at a dose of 1 mg/kg, i.v. Meanwhile, cerebral oxygen consumption was not affected by flunarizine or papaverine. 4) Either of the drugs increased the P0₂ of the cerebral venous blood temporarily and slightly, but significantly, as well as the end tidal CO₂ concentration. These results suggested that flunarizine has a longer acting cerebral vasodilatating effect than papaverine does without any effect on the cerebral oxygen consumption.