Labetalol steady-state pharmacokinetics in hypertensive patients.

1 During chronic treatment of hypertensive patients observed mean steady-state plasma labetalol levels in ten patients were consistently and significantly higher than predicted from initial acute pharmacokinetic analysis. 2 Mean steady-state levels varied from 36 to 183 ng/ml on a chronic dose of 200 mg twice daily. 3 Patients with lower steady-state levels on a fixed dose of labetalol usually required higher maintenance doses to control blood pressure.