INVESTIGATION OF NIMODIPINE PHARMACOKINETICS IN CHINESE PATIENTS WITHACUTE SUBARACHNOID HEMORRHAGE

Nimodipine pharmacokinetics was investigated in 12 Chinese patients wi th acute subarachnoid haemorrhage receiving an IV infusion of 1.6 or 2 mg/h (based on estimated body weight) for 10 days. Peripheral venous blood samples were collected for up to 4 days and plasma nimodipine wa s assayed by GC/ECD. The mean value was taken as the steady state conc entration (C(ss)) and Clearance (CL) (hourly dose/C(ss)) was calculate d. Eight survivors were given oral nimodipine (60 or 90 mg) every 6h ( based on body weight), blood was sampled over 6 h and the plasma nimod ipine level determined. The values for C(ss), CL and CL . kg-1 were 33 .5 mug . l-1, 58 1. h-1 and 1.01 . h-1 . kg-1 respectively; in survivo rs receiving the drug orally, bioavailability of the 30 mg tablet was 9%. In one very sick patient given crushed tablets by naso-gastric tub e, the AUC was very low; in vitro studies indicated that adsorption of nimodipine by the tubing was unlikely to have been the cause. The pha rmacokinetic findings in Chinese patients are comparable to previously reported values in Caucasians.