Objective of this study was to investigate the rate and extent of tramadol bioavailability following evening versus morning administration.
The study was performed following an open, randomised, cross-over study-design. 18 male and female volunteers were enrolled into the study and treated with 200 mg tramadol extended-release capsules (T-long), which were to be taken either in the morning or in the evening.
Plasma concentration versus time profiles obtained after morning and evening administration were almost superimposable for both, tramadol and its active metabolite. Maximum exposure of tramadol and O-desmethyltramadol (geometric means of c(max)-values) as well as extent of exposure (geometric means of AUC(0-48)-values) were comparable after morning and eveningadministration.
Time-point of administration does not have any relevant impact on the rate and extent of absorption in the investigated dosage form. Thus, time-point of administration may be adjusted to the patient's need in a chronopharmacologically optimised way for pain therapy.