Low Dose Versus Normal Dose Ketorolac for Postoperative Pain After Prostatectomy and Hysterectomy

Ketorolac, a non-steroidal anti-inflammatory drug (NSAID), is a commonly used and effective drug for moderate to severe postoperative pain. It is widely prescribed as one of the first steps in acute and postoperative pain since decades. Because of its non-opioid character, this type of drug is safe concerning the risk of addiction and respiratory depression in the postoperative setting, but other side-effects are well known.

Gastro-intestinal (GI) haemorrhage is the most feared complication. The risk of a GI-bleeding increases with age, higher doses and longer duration of therapy. Decrease in renal function seems less important than always assumed. Feldman et al proved that developing renal failure with the use of NSAIDs was rather rare (1,1%) and similar for ketorolac as for opioids. Nonetheless, the risk again increased in a linear fashion with the duration of use. Especially for the postoperative and trauma patient, the fear of platelet inhibition and subsequent bleeding has dominated restriction of its use. Other adverse effects of ketorolac, i.e. cardiovascular toxicity, asthma, allergic reaction, etc., are usually less of a concern for the physician.

In an attempt to reduce these unwanted side effects but still have the benefit of its highly effective analgesic activity, patients should be given the lowest effective dose. Several studies have already demonstrated that ketorolac analgesic efficacy at 10 mg is similar to that at higher doses due to a ceiling effect. Unfortunately, none of the published trials investigated pain scores of the alternative dose beyond 6 hours. Based on the pharmacokinetics of ketorolac, it is possible that the lower dose will loose its analgesic effect after a shorter period. To investigate whether this alternative dose of ketorolac will preserve its analgesic efficacy up to eight hours postoperative, the primary goal of this study will be the pain score after 8 hours, right before the next dose of ketorolac.

Inclusion criteria

• Patients between 18 and 70 years
• Patients undergoing RARP, LAVH or TLH
• ASA 1-3
• Scheduled as inpatient surgery (at least 1 night)
• Body weight > 60 kg

Exclusion criteria

• Refusal of the patient
• Cognitive impairment or no understanding of the Dutch language
• Allergy for salicylates or NSAID
• Pregnancy
• Active or history of peptic ulcer disease
• History of gastro-intestinal hemorrhage or perforation
• History of gastric bypass
• History of renal disease with creatinine > 1 mg/dl
• Haematological disease
• Tromboctopenia < 150000 / µl
• Current anticoagulant use
• Current clopidogrel use
• History of substance abuse or use of medication with a suppressive effect on the central nervous system