BACKGROUND: No large controlled studies to date have examined the hepatic safety of parenteral ketorolac, which is used to treat acutely ill hospitalized patients who may be at greatest risk of liver injury. OBJECTIVE: To measure the association between the use of parenteral ketorolac and subsequent liver injury. METHODS: A nonexperimental cohort study conducted in 35 hospitals in the greater Philadelphia, Pa, region examined 10,272 courses of parenteral ketorolac (the exposed group) and 10,247 courses of parenteral opioid (the comparison group). Liver injury was defined by a modified international consensus definition that relied exclusively on liver function tests. Proportional hazards regression was used to calculate the rate ratio and 95% confidence interval for the association between ketorolac exposure and the occurrence of liver injury, controlling for potentially confounding factors, and to explore the possible effects of duration and dose. RESULTS: The incidence of liver injury was 1.0% in the ketorolac group and 1.2% in the opioid group, yielding an unadjusted rate ratio of 0.77 (95% confidence interval, 0.59 1.01). Simultaneously adjusting for multiple potentially confounding factors did not change this result. There was no evidence for a duration-response relationship (P = .96) or a dose-response relationship (P = .23). We were unable to identify any subgroups that were susceptible to possible hepatotoxic effects of parenteral ketorolac. CONCLUSIONS: This study failed to find evidence of a hepatotoxic effect of parenteral ketorolac use in the hospital setting and provides strong evidence against the existence of a clinically meaningful association between exposure to parenteral ketorolac in the hospital setting and liver injury.
BACKGROUND: No large controlled studies to date have examined the hepatic safety of parenteral ketorolac, which is used to treat acutely ill hospitalized patients who may be at greatest risk of liver injury. OBJECTIVE: To measure the association between the use of parenteral ketorolac and subsequent liver injury. METHODS: A nonexperimental cohort study conducted in 35 hospitals in the greater Philadelphia, Pa, region examined 10,272 courses of parenteral ketorolac (the exposed group) and 10,247 courses of parenteral opioid (the comparison group). Liver injury was defined by a modified international consensus definition that relied exclusively on liver function tests. Proportional hazards regression was used to calculate the rate ratio and 95% confidence interval for the association between ketorolac exposure and the occurrence of liver injury, controlling for potentially confounding factors, and to explore the possible effects of duration and dose. RESULTS: The incidence of liver injury was 1.0% in the ketorolac group and 1.2% in the opioid group, yielding an unadjusted rate ratio of 0.77 (95% confidence interval, 0.59 1.01). Simultaneously adjusting for multiple potentially confounding factors did not change this result. There was no evidence for a duration-response relationship (P = .96) or a dose-response relationship (P = .23). We were unable to identify any subgroups that were susceptible to possible hepatotoxic effects of parenteral ketorolac. CONCLUSIONS: This study failed to find evidence of a hepatotoxic effect of parenteral ketorolac use in the hospital setting and provides strong evidence against the existence of a clinically meaningful association between exposure to parenteral ketorolac in the hospital setting and liver injury.