Permeation of the blood-brain barrier by urapidil and its influence on intracranial pressure in man in the presence of compromised intracranial dynamics.

We studied eight patients undergoing craniotomy for intracerebral tumour surgery requiring monitoring of intracranial pressure. All these patients showed significantly increased systolic arterial pressure, during anaesthesia. Following an average dose of 0.8 +/- 0.22 mg/kg urapidil, systolic arterial pressure returned to baseline values without a significant change in intracranial pressure. In nine patients, urapidil concentrations in plasma and cerebrospinal fluid were assayed following an intravenous injection of urapidil. Urapidil was found in the cerebrospinal fluid in concentrations between 5 and 99 ng/ml after total cumulative bolus injections of 10-75 mg. There is evidence that in clinically applied doses urapidil permeates the blood-brain barrier and reaches cerebrospinal fluid concentrations that allow an interaction with central 5-hydroxytryptamine-1A receptors.