Evidence remains limited on effectiveness of analgesic medication for acute low back pain

Key takeaways:

• Low-certainty evidence suggests that some analgesic treatments may be superior to others in reducing pain.
• Researchers urged physicians use caution when treating patients with analgesic medication.

After reviewing data from nearly 100 randomized controlled trials, researchers reported there is “considerable uncertainty” regarding the safety and efficacy of analgesic medications for acute non-specific low back pain.

Michael A. Wewege, PhD, a research fellow at Neuroscience Research Australia, told Healio that the study was prompted “because medicines are the most common treatment for adults with acute low back pain, and one of the most important questions is, ‘What is the best medicine to use?’ ”

“We wanted to compare the medicines with each other because this is the information patients and physicians want to know, but previous research has mostly focused on comparing medicines to placebo,” he said.

Wewege and colleagues conducted a systematic review and network meta-analysis using data from 98 randomized controlled trials involving 15,134 participants.

The trials analyzed 69 different analgesic medications or combinations — including NSAIDs, paracetamol, opioids, anti-convulsant drugs, skeletal muscle relaxants and corticosteroids — and compared them with other analgesic medications, placebo or no treatment.

Wewege and colleagues examined differences in low back pain intensity after treatment, which was based on a scale from 0 to 100 points.

Overall, “no significant differences were noted between all medicines with large reductions in pain intensity compared with placebo,” the researchers wrote.

The quality of evidence indicating large pain reductions was low with tolperisone (mean difference [MD] = -26.1; 95% CI, -34 to -18.2) and pregabalin (MD = -24.7; 95% CI, -34.6 to -14.7), and very low with aceclofenac plus tizanidine (MD = -26.1; 95% CI, -38.5 to -13.6). These medications were potentially associated with the largest reductions in pain intensity compared with placebo, according to the researchers.

Wewege and colleagues also found that, compared with placebo, increased adverse events during treatment were potentially associated with:

• tramadol (RR = 2.6; 95% CI, 1.5-4.5);
• paracetamol plus sustained release tramadol (RR = 2.4; 95% CI, 1.5-3.8); and
• paracetamol plus tramadol (RR = 2.1; 95% CI, 1.3-3.4).

All three medications had evidence of moderate confidence.

Baclofen (RR = 2.3; 95% CI, 1.5-3.4) may additionally increase the risk for adverse events compared with placebo, but with low confidence, Wewege and colleagues reported.

Because of the limited findings on the treatments’ implications for the primary outcomes, “we urge physicians to use caution when prescribing medicines for acute low back pain, prioritizing safety,” Wewege said.

“Most medicines appear to have little difference in their effect on pain relief, while we have moderate confidence that several medicines may increase the risk of adverse effects,” he said. “Some medicines may offer substantial pain relief, but further research is required to confirm.”

As most patients recover from acute low back pain within 2 to 3 weeks, Wewege recommended they “initially try self-managing their pain with a heat pack or massage and returning to daily activities at a comfortable pace.”

“Patients should always speak to their health professional for individualized advice on their treatment options, which may include medicines,” he said.

References:

• Study finds “considerable uncertainty” around effectiveness and safety of analgesics for low back pain. https://www.eurekalert.org/news-releases/983462. Published Mar 22, 2023. Accessed March 22, 2023.
• Wewege M, et al. BMJ. 2023;doi:10.1136/bmj-2022-072962.