Higher Ketorolac Doses May Not Be More Effective for Treating Acute Pain

Ketorolac doses of 10 to 20 mg are as effective for acute pain relief as 30 mg or higher among adults in the emergency department.

Low-dose parenteral ketorolac may be as effective as high-dose ketorolac for treating adult patients presenting to the emergency department (ED) with acute pain, according to a systematic review and meta-analysis published in Annals of Emergency Medicine.

Patients presenting to the ED with acute pain may receive inadequate treatment. To reduce the use of opioids, nonsteroidal anti-inflammatory drugs (NSAIDs) such as ketorolac are often prescribed. However, ketorolac dosages plateau at a certain point, rendering higher doses no more effective; additionally, patients treated with ketorolac are at greater risk for gastrointestinal (GI) bleeding. Researchers compared the safety and efficacy of different ketorolac doses among patients presenting to the ED with acute pain.

MEDLINE, PubMed, EMBASE, and certain unpublished registries were searched from inception to December 9, 2022 for randomized controlled trials comparing ketorolac dosages for the treatment of acute pain in adult ambulatory patients. Ketorolac dosages of 30 mg or higher were considered high and less than 30 mg were considered low. Analyzed outcomes included pain scores following treatment (reported via the 100 mm visual analog scale), need for rescue analgesia, and presence of adverse events. Data were pooled using random-effects models.

In total, 5 randomized controlled trials comprising 627 patients were included in the review. Two trials were multicenter and 3 single. Children and adults over the age of 70 were excluded in all studies. Two trials used intramuscular ketorolac, while the other 3 used intravenous. Mean baseline pain scores ranged from 68 to 90 mm.

Low-dose ketorolac, as compared to high doses, may have no effect on adverse events, but these patients may need more rescue analgesia.

There was little to no difference in pain scores when comparing low-dose (15-20 mg) vs high-dose ketorolac delivered parenterally (mean difference [MD], 0.05 mm lower; 95% CI, 4.91 mm lower to 5.01 mm higher). Additionally, even lower-dose 10 mg ketorolac may not affect pain scores compared with high-dose (MD, 1.56 mm lower; 95% CI, 8.82 mm lower to 5.69 mm higher).

However, patients receiving low-dose ketorolac may be more likely to need rescue analgesia (relative risk [RR], 1.27; 95% CI, 0.86-1.87). Low-dose ketorolac may not affect adverse events, such as nausea, headache, and dizziness (RR, 0.84; 95% CI, 0.54-1.33).

No trials reported episodes of GI bleeding or renal dysfunction.

This review was limited by imprecision and lower certainty of evidence due to the small number of patients included. Additionally, it is unclear whether study results can be applied to patients at greater risk for adverse events related to NSAID use.

“[I]n adult ED patients treated for acute pain, parenteral ketorolac at doses of 10 to 20 mg is probably as effective as doses of 30 mg or higher,” the study authors wrote. “Low-dose ketorolac, as compared to high doses, may have no effect on adverse events, but these patients may need more rescue analgesia.”


Forestell B, Sabbineni M, Sharif S, Chao J, Eltorki M. Comparative effectiveness of ketorolac dosing strategies for emergency department patients with acute pain. Ann Emerg Med. Published online May 12, 2023. doi:10.1016/j.annemergmed.2023.04.011