Effect of phenoxybenzamine on experimental cerebral arterial spasm in cats.

The effect of topical and intravenous administration of phenoxybenzamine, an alpha adrenergic blocking agent, on experimental vasospasm was studied in cats. Topical application of phenoxybenzamine prevented the occurence of vasospasm without noticeable systemic alpha adrenergic blocking effect. Intravenous use, however, was ineffective in the dosage with which total systemic alpha adrenergic blockade was obtained. Effects of intravenous administration in much larger dosage seemed to be largely due to the non-specific action of phenoxybenzamine on vascular smooth muscle.