Nonnarcotic NSAID Is Safe for Postoperative Pain Control

Continuous infusion of the NSAID ketorolac, a powerful nonopioid analgesic, is a safe therapeutic option for the management of postoperative pain, concludes a double-blind randomized controlled trial.¹
   
Although ketorolac has been associated with risk of bleeding, diathesis, and renal impairment, previous studies have established that a bolus dose of ketorolac is safe.^2-4 To evaluate whether continuous intravenous infusion of ketorolac is also a safe and effective option for postoperative pain control, the study authors compared ketorolac with placebo in 135 patients aged 18 to 75 years who were undergoing either laparoscopic donor nephrectomy (LDN) or percutaneous nephrolithotomy (PNL). Specifically, 68 patients received 90 mg of ketorolac in 1 L of 0.9% normal saline infused at 40 mL/h, and 67 patients received placebo. All study patients had access to opioids for refractory pain.

Interim analysis showed that the difference in mean pain scores between study groups was 0.6, which failed to meet the 1-point threshold established in power calculations. Consequently, the study was stopped after the initial 135 patients were randomized.

Of the included patients, the mean pain score during the first 24 hours after surgery was 1.1 in the ketorolac group and 0.6 in the placebo group (P=.10). The mean morphine equivalents that study participants used were 38 mg in the ketorolac group and 41 mg in the placebo group (P=.79). In addition, the change between preoperative and postoperative hemoglobin levels did differ significantly between study groups, suggesting that there is no increased risk of bleeding in the ketorolac group.

Although NSAID use can cause acute renal failure, none of the patients in this study had any renal complications. Postoperative urine output was lower in the ketorolac group than in the placebo group (142 mL/h vs 175 mL/h, respectively). However, the urinary output in both groups was adequate, and the difference in serum creatinine levels between groups was not statistically significant. The study authors write that the use of adequate intravenous fluids to prevent intravascular dehydration may be renoprotective by mitigating the potential detrimental effects of ketorolac on glomerular filtration rate by increasing hydrostatic pressure and volume.

The study authors hope that these findings offer clinicians guidance in the use of a new, safe option for the management of postoperative pain.

Pertinent Points:
- Ketoroloac, an NSAID that can be administered both intravenously and intramuscularly, appears to be a safe option for pain control in the first 24 hours after surgery.
- This study is the first to examine use of ketorolac administered as a continuous infusion for postoperative pain control.

References:

1. Grimsby GM, Conley SP, Trentman TL, et al. A double-blind randomized controlled trial of continuous intravenous ketorolac vs placebo for adjuvant pain control after renal surgery. Mayo Clin Proc. 2012;87:1089-1097.
2. Breda A, Bui M, Liao J, Schulam PG. Association of bowel rest and ketorolac analgesia with short hospital stay after laparoscopic donor nephrectomy. Urology. 2007;69:828-831.
3. Freedland SJ, Blanco-Yarosh M, Sun SJ, et al. Effect of ketorolac on renal function after donor nephrectomy. Urology. 2002;59:826-830.
4. Freedland SJ, Blanco-Yarosh M, Sun JC, et al. Ketorolac-based analgesia improves outcomes for living kidney donors. Transplantation. 2002;73:741-745.