Premium
Rising Multiple‐Dose Pharmacokinetics of Labetalol in Hypertensive Patients
Author(s) -
Chung Menger,
Leitz Frederick H.,
Maier Gary,
Patrick James E.,
Gural Richard P.,
Symchowicz Samson
Publication year - 1986
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1002/j.1552-4604.1986.tb03518.x
Subject(s) - labetalol , pharmacokinetics , pharmacology , medicine , absorption (acoustics) , oral administration , steady state (chemistry) , anesthesia , chemistry , blood pressure , physics , acoustics
Labetalol a drug possessing both alpha‐ and beta‐adrenergic blocking activities, is used in the treatment of hypertension. The current study was undertaken to elucidate the steady‐state pharmacokinetics of labetalol following a rising oral multiple‐dosage regimen. Twelve patients received oral labetalol every 12 hours for 18 days. An initial dose of 100 mg was increased at three‐day intervals to 200, 300, 400, and 600 mg q12h. Selected blood samples were taken at various times following drug administration at each dose level and analyzed for labetalol levels by a specific high‐performance liquid chromography assay. The pharmacokinetics of labetalol are best described by a two‐compartment open model with first‐order absorption. The half‐lives of the absorption, distribution, and elimination phases are 0.6, 1.3, and 8.3 hours, respectively. The steady‐state plasma drug concentrations are predictable from the pharmacokinetic data and are in good agreement with the observed values. Steady‐state levels are reached by the third day at each dose level studied and increase proportionally with dose.