Ibuprofen, Ketorolac, and Diclofenac Similarly Effective for Low Back Pain

A man taking medication
A man taking medication
The comparative efficacy of nonsteroidal anti-inflammatory drugs for lower back pain was examined.

There are no significant differences in results between ibuprofen, ketorolac, and diclofenac as first-line treatments for nonradicular low back pain, according to a study recently published in Academic Emergency Medicine.

This double-blind, three-armed comparative effectiveness study included 198 participants who had been admitted to the emergency department due to musculoskeletal low back pain. These participants were randomly assigned to receive 600 mg ibuprofen (n=66), 10 mg ketorolac (n=66), or 50 mg diclofenac (n=66), taken every 8 hours as needed.

The primary outcome was change in the Roland-Morris Disability Questionnaire (RMDQ) score (in which lower scores indicate better outcomes for low back pain) between days 0 and 5, which was ascertained via telephone interview 2 and 5 days after admittance. As secondary outcomes, the study researchers assessed stomach irritation and pain intensity (none, mild, moderate, severe).

Primary outcome differences were analyzed using a one-way ANOVA.

Among the 198 participants enrolled, day 5 RMDQ improvements were as follows: ibuprofen (9.4±9.5 pts), ketorolac (11.9±8.8 pts), and diclofenac (10.9±9.4 pts) (overall ANOVA P =.34). Mild pain on day 5 was experienced by 28% (n=17) of those given ibuprofen, 46% (n=27) of those given ketorolac, and 40% (n=25) of those given diclofenac, while no pain was experienced by 33% (n=20), 34% (n=20), and 32% (n=20), respectively.

This resulted in an 18% (95% CI, 2-34) difference between ibuprofen and ketorolac (P =.04). Stomach irritation was reported by 26% (n=16) of those given ibuprofen, 5% (n=3) of those given ketorolac, and 9% (n=6) of those given diclofenac (P <.01).

Limitations to this study include highly socioeconomically depressed study regions (and hence has uncertain generalizability), the potential for increased side effects with the 600 mg ibuprofen dose, a lack of assessment of baseline pain scores, a lack of record of analgesic use, and the fact that the study was underpowered for certain outcomes.

The study researchers concluded that “there were no important differences between groups with regard to the primary outcome.” However, they noted that “[these] data do not rule out [the] possibility that ketorolac results in better pain relief and less stomach irritation than ibuprofen.”


Irizarry E, Restivo A, Salama M, et al. A randomized controlled trial of ibuprofen versus ketorolac versus diclofenac for acute, nonradicular low back pain [published online June 16, 2021]. Acad Emerg Med. doi:10.1111/acem.14321