Amitriptyline Dosage Schedule, Sampling Time and Tricyclic Plasma Levels

Abstract

SummaryPlasma levels of amitriptyline and nortriptyline were similar in ten depressed patients after administration of amitriptyline hydrochloride in three divided doses or as a single daily dose. Maximum comparability of the plasma levels is achieved by sampling 12 to 16 hours after the single daily dose, or 3 to 7 hours after the morning dose on a thrice-daily schedule. Owing to the long biological half-life of these drugs, therapeutic plasma levels are maintained on a once a day dosage schedule, and the need for sustained release preparations appears questionable.