Aim: This study reassesses the efficacy and safety of antidepressants in treating nonspecific chronic low back pain (NCLBP).Materials & methods: A systematic review was conducted following PRISMA guidelines, including randomized clinical trials (RCTs) from PubMed, Embase, Scopus, LILACS, SciELO and Cochrane CENTRAL, published through August 2024. Studies compared antidepressants with placebo or active comparators. The primary outcomes were pain relief and quality of life. Protocol registration: www.crd.york.ac.uk/prospero identifier is CRD42023307516.Results: Nine RCTs involving 1758 patients were analyzed. The antidepressants examined included duloxetine, escitalopram, bupropion, amitriptyline, imipramine and desipramine. Duloxetine 60mg significantly reduced pain (MD=-0.57; 95% CI=-0.78 to -0.36) and improved quality of life compared with placebo, with side effects that were generally tolerable. Notably, higher doses of duloxetine (120mg) were associated with an increase in adverse events. However, other antidepressants like amitriptyline and escitalopram demonstrated only modest or inconsistent effects.Conclusion: Duloxetine at 60mg provides consistent pain relief and improves the quality of life in NCLBP, but higher doses increase adverse events. Escitalopram might offer modest benefits but should be considered a third-line treatment. Other antidepressants, such as amitriptyline, bupropion, imipramine and desipramine, have limited evidence supporting their efficacy and are associated with adverse effects.