Ketorolac and the Kidney
Source: Feldman HI, et al. Ann Intern Med 1997;126:193-199.
A recent multicenter, retrospective, cohort study by Feldman et al was undertaken to establish the risk of acute renal failure (ARF) associated with the NSAID ketorolac. Inpatients receiving over 10,000 courses of the drug parenterally were compared with a similar number of patients receiving courses of parenteral opioid analgesics. Subjects were matched by hospital, admitting service, and date of therapy initiation. Long-term dialysis patients were excluded. ARF was defined in two ways: principally, by an elevation in creatinine that met specific absolute and relative (to baseline) criteria, and, secondarily, by chart notation of acute renal failure in addition to this laboratory evidence.
ARF occurred infrequently, regardless of how it was defined. The incidence was the same for both the ketorolac and opioid groups: 1.1%. ARF occurred in no one under 15 years of age, in less than 1% of patients ages 15-64, and in 2% of patients ages 65 or older. However, there was a significantly higher rate of ARF in the ketorolac group when the course of therapy was longer than five days. The study had limited power to identify a specific subgroup at risk for ARF; although one was not found, the incidence of ARF (regardless of drug) was significantly increased in patients with several predisposing conditions, including chronic renal disease, cirrhosis, hypertension, cancer, and concomitant use of aminoglycoside or other antibiotics.
Comment by Richard A. Harrigan, MD
This study provides reassurance that short-course ketorolac therapy is relatively unlikely to cause acute renal insufficiency. Keeping in mind that the study population consisted of hospitalized (and presumably "sick") patients, the physician may feel more comfortable with the use of ketorolac in some aspects of care. The authors reference several case reports of ARF after ketorolac use, some of which occurred after only a single dose of the agent. This is the first study that compares the rate of ARF in patients receiving ketorolac with appropriate controls. The study also reminds us which patients are already at risk for ARF; I would be less likely to use ketorolac in patients with the predisposing conditions highlighted in the study and listed above.
The issue of ketorolac and gastrointestinal hemorrhage is another concern; these authors have published previously with respect to this complication.1 Finally, we must consider cost. At our hospital, the pharmacy costs for ketorolac 30 mg IV are $7.19, whereas pharmacy costs for meperidine 50 mg IV and morphine 5 mg IV are $0.35 and $0.49, respectively.