Endogenous Opioid Peptide Responses to Opioid and Anti-Inflammatory Medications Following Eccentric Exercise-Induced Muscle Damage. Peptides [Peptides] Journal article

To determine the effects of Vicoprofen(R), Ibuprofen, and a placebo on the responses of endogenous opioid peptides following eccentric exercise-induced muscle damage thirty-six healthy men (age: 22.8 yrs; height: 178.8+/-6.2 cm; body mass 78.9+/-13.7 kg; body fat: 15.8+/-6.5%) volunteered to participate in the study. Each participant was evaluated for pain 24 hours post and randomly assigned to an experimental group: VIC (Vicoprofen(R)), IBU (Ibuprofen) (IBU), or P (placebo). Medication was give 4 times daily (i.e., VIC (hydrocodone bitartrate 7.5 mg with ibuprofen 200 mg), and IBU 200 mg. Blood was obtained at rest and at 24, 48, 72, 96 and 120 hrs following the eccentric exercise damage protocol. No significant changes for B-END were observed in the resting values over the recovery period among any of the treatment conditions. Conversely for plasma P-F, VIC and IBU had significantly (P < 0.05) higher plasma concentrations of P-F above placebo at 24, 48, 72, and 96 hrs with VIC higher than IBU and placebo conditions at 120 hrs. Significant resting elevations were observed for P-F from pre-exercise at 48, 72, 96, and 120 hrs for VIC; at 72 and 96 hrs for IBU; and at 72 for placebo treatment. Less tissue damage (MRI analyses), improved physical function as well as reduced pain was observed for the VIC condition over IBU and placebo. These data indicate that exogenous medications appear to be differentially stimulating the peripheral (adrenal medulla) opioid neuroendocrine responses as measured by plasma concentrations.

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