Absorption
Mean absolute bioavailability of tramadol is 75% (immediate release), 85% to 90%
( Ultram ER ), or 95% ( Ryzolt ). T max is 2 h (immediate release), 4 h ( Ryzolt ), and
12 h ( Ultram ER ). Steady-state plasma concentrations of tramadol and the metabolite
are achieved within 2 days (immediate release, Ryzolt ) and within 4 days ( Ultram
ER ). Food delays T max by 30 min (orally disintegrating tablets). High-fat meals
increased T max by 3 h and decreased C max and AUC by 28% and 16%, respectively
( Ultram ER ).