Hi - Just wanted to let everyone know that I reviewed the prescribing information for Ultram (Tramadol) vs. Ultram ER, the extended release formulation since everyone was talking about the new ER version. Mean peak plasma concentrations (highest level of the drug and metabolite in the blood stream) for the ER formulation don't occur until 12-15 hours AFTER dosing. Steady state plasma levels take 4 days of dosing to achieve. The immediate release tablets achieve a mean peak plasma concentration (highest level of the drug and metabolite in the blood stream) in 2 - 3 hours and steady state levels are achieved in 2 days. SO - don't expect pain relief within a couple of hours if you switch to the ER formulation.