Comparative pharmacokinetics of a once-daily tramadol extended-release tablet and an immediate-release reference product following single-dose and multiple-dose administration.

The pharmacokinetics of a once-daily formulation of tramadol (Tramadol Contramid OAD 200-mg tablets) following single-dose and multiple-dose administration was compared with that of an immediate-release product (tramadol IR 50-mg tablets) in 2 separate studies. In both studies, AUC parameters met bioequivalence criteria, whereas C(max) of Tramadol Contramid OAD was lower than that of tramadol IR following a 200-mg daily dosage. After single-dose administration, the mean tramadol concentration at 1 hour postdose was within the range associated with analgesic efficacy (>100 ng/mL), and the mean concentration remained above this level for the remainder of the dosing interval.