'Little justification' for antidepressants in back pain, may be effective in OA
Antidepressants are mostly ineffective for treating back pain, but may be beneficial for osteoarthritis and sciatica, according to data published in BMJ.
“We realized that antidepressants are commonly used in clinical practice to reduce pain in people with back pain and osteoarthritis, and that several guidelines recommend their use,” Giovanni E. Ferreira, PhD, of the University of Sydney, told Healio Rheumatology. “However, all systematic reviews summarizing the findings from randomized trials were either outdated or had methodological problems that did not allow a comprehensive assessment of the effects of these medicines.”
To update the evidence on the use of antidepressants for back pain and OA, Ferreira and colleagues conducted a systematic review and meta-analysis. Eligible studies included randomized controlled trials comparing the efficacy or safety — or both — of any antidepressant drug with a placebo, in patients with lower back or neck pain, sciatica or hip or knee OA. Data sources included Medline, Embase, Cochrane Central Register of Controlled Trials, CINAHL, International Pharmaceutical Abstracts, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform, from inception to Nov. 15, 2020, and updated May 12, 2020.
In all, the researchers included 33 trials in their analysis. Two independent reviewers conducted data extraction, with pain and disability as the primary outcomes. The secondary outcome was safety, including any adverse event, serious adverse events and the proportion of participants who withdrew due to adverse events. All pain and disability scores were converted to a scale of 0-100. The researchers used a random effects model to calculate weighted mean differences and confidence intervals.
Bias risk was assessed using the Cochrane Collaboration’s tool, while evidence certainty was analyzed with the grading of recommendations assessment, development and evaluation (GRADE) framework.
According to the researchers, moderate-certainty evidence demonstrated that serotonin-noradrenaline reuptake inhibitors (SNRIs) reduced back pain (mean difference = –5.3; 95% CI –7.31 to –3.30) at 3 to 13 weeks. Meanwhile, low-certainty evidence showed that SNRIs reduced osteoarthritis pain (–9.72; 95% CI, –12.75 to –6.69) at 3 to 13 weeks. Very low-certainty evidence demonstrated that SNRIs reduced sciatica at 2 weeks or less (–18.6; 95% CI, –31.87 to –5.33) but not at 3 to 13 weeks (–17.5; 95% CI, –42.9 to 7.89).
In addition, low- to very low-certainty evidence showed that tricyclic antidepressants (TCAs) failed to reduce sciatica at 2 weeks or less (–7.55; 95% CI, –18.25 to 3.15) but succeeded at 3 to 13 weeks (–15.95; 95% CI, –31.52 to –0.39) and at 3 to 12 months (–27; 95% CI, –36.11 to –17.89).
There was moderate-certainty evidence that SNRIs reduced disability from back pain at 3 to 13 weeks (–3.55; 95% CI, –5.22 to –1.88) and disability due to osteoarthritis at 2 weeks or less (–5.1; 95% CI, –7.31 to –2.89), with low-certainty evidence at 3 to 13 weeks (–6.07; 95% CI, –8.13 to –4.02). TCAs and other antidepressants, meanwhile, failed to reduce pain or disability from back pain.
However, despite findings suggesting a possible benefit, Ferreira and colleagues advised caution when interpreting their findings for OA and sciatica.
“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,” Ferreira said. “Taking antidepressants may increase your chances of experiencing some side effects, and this should be discussed with your doctor or pharmacist.”
“Most low back pain guidelines currently recommend antidepressants for back pain and osteoarthritis,” he added. “Our findings show that there is little justification for recommending antidepressants for people with back pain. For osteoarthritis and sciatica, whilst these medicines may be effective, guidelines should emphasize that the current evidence is uncertain, and patients should be made aware of this piece of information as well to make an informed decision.”