The efficacy of intramuscular ketorolac in combination with intravenous PCA morphine for postoperative pain relief

Abstract

Study objective: To examine the efficacy of intramuscular (IM) ketorolac used in combination with intravenous (IV) patient-controlled analgesia (PCA) morphine for postoperative pain relief following intra-abdominal gynecologic surgery.

Design: Randomized, double-blind, placebo-controlled study.

Setting: Patient care unit at a university medical center.

Patients: Thirty-five healthy women undergoing intra-abdominal gynecologic surgery who requested postoperative PCA.

Interventions: Postoperatively, all patients received IV PCA morphine, with the PCA device programmed to deliver a maximum of 1 mg every 6 minutes (maximum of 30 mg over 4 hours). In addition, patients received one of three regimens: (1) IM saline every 6 hours; (2) IM ketorolac 30 mg while in the postanesthesia care unit (PACU), followed by 15 mg every 6 hours; or (3) IM ketorolac 60 mg while in the PACU, followed by 30 mg every 6 hours.

Measurements and main results: Patients were assessed at regular intervals. Visual analog scale (VAS) scores were used to assess analgesia and patient satisfaction with therapy. Data on morphine usage were obtained from the PCA device, and the frequency and severity of adverse effects were assessed for the presence or absence of side effects. Cumulative morphine dosages were lower (p less than 0.05) in both ketorolac groups at 12, 18, and 24 hours. VAS scores and the frequency of side effects did not differ significantly among groups.

Conclusions: IM ketorolac significantly decreased PCA morphine requirements. The analgesic effects of the two drugs appear to be additive.