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.


METHODS
Prospective, randomized investigation.


METHODS
Tertiary care university teaching hospital.


METHODS
Fourteen patients 60 years of age or older who were undergoing general surgery.


METHODS
A single dose of meperidine 0.75 mg/kg given intramuscularly at either a deltoid or gluteal site.


METHODS
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 ng/mL deltoid). Although pain scores were similar for the two groups, four of the patients in the group given gluteal injection required additional breakthrough pain management within 4 hours of meperidine injection compared with one patient in the group given deltoid injection.


CONCLUSIONS
There is no obvious relationship between meperidine pharmacokinetic and pharmacodynamic parameters, regardless of intramuscular injection site. Breakthrough pain is common when patients are given intramuscular injections postoperatively, particularly when the gluteal route is used. When meperidine is used for analgesia in elderly postoperative patients, consideration should be given to more rapid and predictable routes (e.g., intravenous injection) of meperidine administration.
Erstad
B L
BL
Department of Pharmacy Practice and Science, College of Pharmacy, University of Arizona, Tucson 85721, USA.
Meeks
M L
ML
Chow
H H
HH
Rappaport
W D
WD
Levinson
M L
ML
D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology*; D005260:Female; D005853:Geriatrics; D006207:Half-Life; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008614:Meperidine / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology*; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy*; D011446:Prospective Studies; D011897:Random Allocation
D000701:Analgesics, Opioid; D008614:Meperidine