BIOAVAILABILITY OF LABETALOL IN PATIENTS WITH END-STAGE RENAL-DISEASE

The pharmacokinetics and pharmacodynamics of labetalol were assessed after a single oral and intravenous dose in eight patients with end-stage renal disease (ESRD) maintained on chronic hemodialysis, and in eight age-and sex-matched normal volunteers. The mean area under the serum concentration-time curve, volume of distribution, clearance, and terminal elimination half-life values after a single intravenous dose of 0.5 mg/kg of labetalol were not significantly different between ESRD patients and normal volunteers. Similarly, the absolute bioavailability of an oral dose of 200 mg of labetalol was 0.33 in ESRD patients and was not significantly different from that of normal volunteers (0.26). However, a significant decrease in the area under the mean blood pressure-time curve was found after a single oral dose in ESRD patients, which was not observed in normal volunteers. The pharmacokinetics of labetalol were not associated with changes in blood pressure. Thus, when given orally to the ESRD patient, labetalol should be slowly titrated and the blood pressure closely monitored.