Tramadol is a synthetic, centrally acting
analgesic. A sustained-release (SR)
capsule formulation of
tramadol gradually releases active
drug, allowing for twice-daily dosing. Compared with
tramadol SR
tablets,
tramadol SR capsules produced a smoother plasma concentration profile, with more gradual absorption and lower peak concentrations. There was less intra- and intersubject variability in
tramadol plasma concentrations with SR capsules versus SR.
Tramadol SR capsules had identical bioavailability to
tramadol immediate-release (IR) capsules with lower peak concentrations and less fluctuation in plasma concentrations.
Tramadol SR 100 mg capsules administered twice daily had equivalent efficacy to
tramadol IR 50 mg capsules administered four times daily in the treatment of moderate to severe chronic
low back pain in a well designed study. Patients receiving
tramadol SR capsules were significantly less likely than those receiving
tramadol IR capsules to report
nausea. Starting treatment with
tramadol SR capsules at a dosage of 50 mg twice daily with subsequent dose escalation resulted in improved tolerability in patients with moderate to severe
chronic pain. The lowest
tramadol SR
capsule dosage of 50 mg twice daily (administered to 35% of patients with moderate to severe non-
oncological pain) significantly improved
pain intensity and frequency in 83.4% and 70.4% of patients, respectively, in a postmarketing observational study evaluating
tramadol SR capsules 50-200 mg twice daily (n = 3888).