A Pharmacokinetic, Tolerability, and Safety Study of ULTRAM ER in Children With Pain

This is a multicenter, open-label (all people know the identity of the intervention), 2-group, single dose study. Within each group of participants for Parts 1 and 2, at least 1/3 of the participants will be female, at least 1/3 of the participants will be male, at least 1/3 of the participants will be below the age of 8 years, and at least 1/3 of the participants will be above the age of 10 years. Participants will be assigned to 1 group only. Each group of participants will receive a single oral dose of ULTRAM ER on 1 occasion. Group 1 will receive a dose of ULTRAM ER that is closest to 2 mg/kg, based on the participant's body weight and adjusting the dose in 25 mg increments. Following completion of all evaluations of Group 1, the pharmacokinetic data will be evaluated to target a dose for Group 2 that will achieve a level of exposure similar to that seen with a single 200 mg ULTRAM ER dose in adults. The maximum dose of ULTRAM ER should not exceed 6 mg/kg or 300 mg. When the study physician, the investigators, and the medical monitors agree that the PK of the drug is well-characterized and that the drug is well tolerated, enrollment will begin for Group 2 of the study. The sponsor's responsible Medical Officer will evaluate the safety of the calculated dose in Group 2 participants by evaluation of adverse drug events paying particular attention to events suggestive of either opioid toxicity or serotonin toxicity.