Site-Specific Pharmacokinetics and Pharmacodynamics of Intramuscular Meperidine in Elderly Postoperative Patients

OBJECTIVE:To examine and compare the pharmacokinetics and pharmacodynamics of meperidine when administered intramuscularly at gluteal and deltoid sites in elderly postoperative patients.DESIGN:Prospective, randomized investigation.SETTING:Tertiary care university teaching hospital.PATIENTS:Fourteen patients 60 years of age or older who were undergoing general surgery.INTERVENTION:A single dose of meperidine 0.75 mg/kg given intramuscularly at either a deltoid or gluteal site.MAIN OUTCOME MEASURES:Pharmacokinetic (based on concentration—time curves) and pharmacodynamic (i.e., pain scales, need for additional pain medication) comparisons were made, based on site of meperidine injection.RESULTS:No statistically significant differences were found in the maximum plasma concentration, volume of distribution, or clearance of meperidine by site of injection. Substantial interpatient variability in pharmacokinetic parameters was noted for both sites (range of maximum concentrations: 191–500 ng/mL gluteal, 166–374 ...