For a sudden bad back, the benefit is small and the reviews disagree
Cochrane pooled 32 trials and found these drugs better than placebo for acute low back pain. A network of 98 trials rated every painkiller it tested at low or very low confidence.
What the study found
Acute back pain: a small clear benefit, or nothing you can trust
A Cochrane review of 32 trials found non-steroidal anti-inflammatory drugs, or NSAIDs, better than placebo for acute low back pain, with the disability result graded high certainty. A network of 98 trials rated every analgesic tested, NSAIDs included, at low or very low confidence.
The caveat · Only 7 of 32 trials rated low-bias
Both reviews agree any benefit is small, and the Cochrane authors call the size probably not clinically relevant. Low confidence means the evidence cannot settle the question, not that the drugs were shown not to work. Only 7 of the 32 trials in the Cochrane review were judged at low risk of bias, almost half were industry-funded, and most were never registered. Neither review followed anyone long enough to speak to repeated use.
What we don't know
Two reviews of acute low back pain agree which way anti-inflammatories point; they disagree on whether trials this small, mostly unregistered and often industry-funded can say so.