Khankhel N, Friedman BW, Baer J, et al. Topical Diclofenac Versus Oral Ibuprofen Versus Diclofenac + Ibuprofen for Emergency Department Patients With Acute Low Back Pain: A Randomized Study. Ann Emerg Med. 2024 Mar 2:S0196-0644(24)00075-1. doi: 10.1016/j.annemergmed.2024.01.037. (Original study)

STUDY OBJECTIVE: Topical nonsteroidal anti-inflammatory drugs (NSAIDs) are useful for a variety of musculoskeletal injuries. It is not known whether topical NSAIDs should be used for patients presenting with acute nonradicular musculoskeletal low back pain.

METHODS: We conducted a randomized, placebo-controlled double-blind study in which patients 18 to 69 years of age visiting the emergency department (ED) with acute, nontraumatic, nonradicular, musculoskeletal low back pain were randomized at the time of discharge to treatment with 400 mg oral ibuprofen + placebo topical gel, 1% diclofenac topical gel + oral placebo, or 400 mg ibuprofen + 1% diclofenac topical gel. We measured outcomes using the Roland Morris Disability Questionnaire (RMDQ), a 24-item yes/no instrument about the effect of back pain on a respondent's daily activities. The primary outcome was change in RMDQ score between ED discharge and 2 days later. Medication-related adverse events were elicited by asking whether the study medications caused any new symptoms.

RESULTS: In total, 3,281 patients were screened for participation, and 198 were randomized. Overall, 36% of the population were women, the mean age was 40 years (standard deviation, 13), and the median RMDQ score at baseline was 18 (25th to 75th percentile: 13 to 22), indicating substantial low back-related functional impairment. In total, 183 (92%) participants provided primary outcome data. Two days after the ED visit, the ibuprofen + placebo group had improved by 10.1 (95% confidence interval [CI] 7.5 to 12.7), the diclofenac gel + placebo group by 6.4 (95% CI 4.0 to 8.8), and the ibuprofen + diclofenac gel by 8.7 (95% CI 6.3 to 11.1). The between-group differences were as follows: ibuprofen versus diclofenac, 3.7 (95% CI 0.2 to 7.2); ibuprofen versus both medications 1.4 (95% CI -2.1 to 4.9); and diclofenac versus both medications, 2.3 (95% CI -5.7 to 1.0). Medication-related adverse events were reported by 3/60 (5%) ibuprofen patients, 1/63 (2%) diclofenac patients, and 4/64 (6%) patients who received both.

CONCLUSION: Among patients with nontraumatic, nonradicular acute musculoskeletal low back pain discharged from an ED, topical diclofenac was probably less efficacious than oral ibuprofen. It demonstrated no additive benefit when coadministered with oral ibuprofen.

Discipline Area Score
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Comments from MORE raters

Physician rater

Although it may seem like a minor concern to many, this well-designed RCT provides the current best available answer on the usefulness of diclofenac gel for uncomplicated lower back pain: the answer is that it is inferior to oral ibuprofen and does not add to it when used together. The fact that the authors provide medication for only two days and measure the outcome at 7 may seem problematic, but since the first two days are likely the most symptomatic, this design issue may not be a major clinical problem. Negative studies are important!
Comments from PAIN+ CPN subscribers

Prof. Mike Poling (3/22/2024 8:52 AM)

At 1%, this isn't even high enough to be equivalent to OTC Extra Strength Voltaren. If you want a true evaluation, use compounded 6-10% diclofenac topically. However, given the depth source of most issues in the lumbar spine (70%+ are discogenic in nature and 15% zygapophyseal joint related, with associated muscle spasms being a symptom, not a cause), topicals in the lumbar spine are unlikely to be effective. Depth is typically limited to 2" for dispersion.