Although antidepressants are often used for back pain as well as knee and hip osteoarthritis, a systematic review and meta-analysis suggests these drugs may have no clinically relevant benefit for those conditions. Researchers analyzed data from 33 randomized controlled trials (5,318 participants) that compared the safety and efficacy of any type of antidepressant to a placebo for individuals with a range of musculoskeletal conditions including low back pain, neck pain, Sciatica, or hip or knee osteoarthritis. The primary outcome was reduction in pain and disability. Researchers created a common 0-100 rating score across all the trials, with 0 indicating no symptoms and 100 indicating the worst possible symptoms. They set a predetermined threshold for clinical relevance of at least a mean between-group difference of 10 points. They found a small, non-clinically relevant benefit for back pain (mean difference -5.30) and osteoarthritis (mean difference -9.72) with serotonin noradrenaline reuptake inhibitors (SNRIs), with moderate certainty evidence. Moderate certainty evidence also showed SNRIs could reduce disability from back pain (mean difference -3.55) and osteoarthritis (mean difference -5.10). Short-term SNRIs appeared to benefit Sciatica (mean difference -18.60) but researchers described this as very low certainty evidence. Longer use of tricyclic antidepressants also appeared to benefit Sciatica (mean difference -15.95) but this was also low certainty evidence. "Our findings show that antidepressants are largely ineffective for back pain, but may be beneficial for osteoarthritis and Sciatica," said lead study author Giovanni Ferreira of the Institute for Musculoskeletal Health at the University of Sydney, in Australia. "However, we would advise caution when interpreting our findings for osteoarthritis and Sciatica," Ferreira said by email. "Most trials in people with osteoarthritis were sponsored by pharmaceutical companies that stand to gain a lot if the drug is shown to be beneficial, and trials in people with Sciatica were small and poorly conducted and hence the findings are less certain." Adverse events may also be more common with SNRIs (relative risk 1.23), although this evidence was of low certainty. There appeared to be no increased risk of adverse events with other antidepressants in the study. One limitation of the study is that researchers lacked data on varied doses of antidepressants, and were unable to determine how dosage might impact pain and disability or the risk of adverse events. "Few people with back pain or osteoarthritis will gain a worthwhile reduction in pain from taking antidepressants," said Martin Underwood, a researcher at the University of Warwick in the UK and co-author of an editorial accompanying the study in The BMJ. "Doctors, and other health professionals, need to find better ways of helping people to live better with these disorders without using drugs," Underwood said by email. —Lisa Rapaport Source
