Urapidil permeates the intact blood-brain barrier.

OBJECTIVE

To determine the plasma and cerebrospinal fluid (CSF) levels of urapidil after i.v. administration and the effect on CSF serotonin and 5-hydroxyindoleacetic acid (5-HIAA) concentrations.

DESIGN

Open, single-dose study.

SETTING

Post-surgery following neurosurgical removal of the hypophysis (n = 5) or aneurysm clipping (n = 1).

PATIENTS

6 patients, aged 32-71 years, with intact blood-brain barrier (BBB); 1 patient was studied twice.

INTERVENTIONS

Single dose of 25 mg urapidil i.v. as prophylaxis of BP increase during extubation or as treatment of hypertensive episodes.

MEASUREMENTS AND RESULTS

Urapidil, serotonin and 5-HIAA were measured by HPLC in CSF during 8 h after urapidil administration. Urapidil was detected in CSF as soon as 5 min after injection in 3 patients. The concentration ratio of plasma/CSF after the distribution phase was about 5:1. No significant effect on serotonin and 5-HIAA in CSF was seen.

CONCLUSION

After administration of a therapeutic dose, urapidil permeates the BBB and may interact with central 5-HT1A-receptors.