[Effects of (E)-1-[bis (4-fluorophenyl)methyl]-4-(3-phenyl-2-propenyl) piperazine dihydrochloride(flunarizine) on cerebral circulation].

Effects of flunarizine (0.3-3 mg/kg, i.v.) on cerebral circulation were compared with those of cinnarizine (0.3-3 mg/kg, i.v.) and papaverine (0.1-1 mg/kg, i.v.) in anaesthetized dogs and cats. In dogs any of the three drugs caused a dose-related increase in vertebral, common carotid, and femoral arterial blood flow, while a transient decrease in renal blood flow was seen. In particular, the vasodilatation caused by flunarizine and cinnarizine was much more marked in the vertebral vascular beds as compared to the other ones. Flunarizine (10 and 30 mg/kg, intraduodenally) caused a greater and more prolonged increase in the vertebral blood flow than cinnarizine and papaverine did when they were used in the same doses. Concerning the local circulation in cats, flunarizine and cinnarizine produced a marked flow increase in the cerebellar cortex, and apparent blood flow and pO2 increases in the cerebral cortex with no observable concomitant changes in arterial blood pO2 and pCO2; but a slight decrease in hippocampal blood flow without any consistent effect in hypothalamic blood flow. In this study, flunarizine was shown to have a more prolonged pharmacological activity on the responses of the cerebral circulation than equal doses of cinnarizine or papaverine.