Be Cautious in Using Ketorolac in Patients with Marginal Urine Output or Renal Function
Angela D. Shoher MD
Ketorolac is a nonsteroidal inflammatory agent with greater systemic analgesic properties than anti-inflammatory activity. The onset and efficacy of its analgesic properties are claimed to be comparable with those of morphine. Ketorolac works by competitively inhibiting the cyclooxygenase isoenzymes (COX-1 and COX-2). These enzymes catalyze the conversion of arachidonic acid to prostaglandins. Prostaglandins E and F appear to be responsible for sensitizing pain receptors, explaining the analgesic properties of the drug. Bioavailability of the drug is 100% after oral, intravenous, or intramuscular administration. Food only decreases the rate but not the extent of absorption. Ketorolac is also 99% bound to albumin. It is metabolized by the liver to a form that is less than 1% as potent as the original form.