Methods and findings in experimental and clinical pharmacology
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Methods Find Exp Clin Pharmacol · Apr 1996
Randomized Controlled Trial Comparative Study Clinical TrialRespiratory and analgesic effects of meperidine and tramadol in patients undergoing orthopedic surgery.
The respiratory and analgesic effects of i.v. meperidine, tramadol and their correlation with plasma concentrations of meperidine, tramadol and O-demethyltramadol were determined. Forty-eight patients after total hip or knee replacement were randomly distributed into 3 groups (n = 16 each). At the time of analgesia request, they received in a double-blind manner, i.v. single doses of 100 mg meperidine, 100 mg tramadol, or saline. ⋯ A negative correlation (r = -0.99) between analgesia and tramadol concentrations and a poor positive correlation (r = +0.54) with O-demethyltramadol (a metabolite of tramadol) was observed. Pain intensity differences correlated negatively with meperidine plasma concentrations during the first 30 min (r = -0.97) and positively thereafter (r = +0.92). In the present study, meperidine and tramadol produced comparable analgesia, with a different time course profile, but meperidine induced sedation and respiratory depression while tramadol did not.