Nephrotoxicity of methadone: a systematic review

BACKGROUND: Methadone is commonly administered for chronic pain relief and treatment of opioid dependence. Concurrent with its increased consumption, toxicities and fatalities have increased. One of the adverse effects of opioid analgesics, including methadone, is that of nephrotoxicity. Opioids can have an effect on renal function through several different mechanisms. METHODS: We searched common bibliographical databases for the terms methadone, toxicity, poisoning, kidney, renal, and nephrotoxicity and summarize our findings in this review. RESULTS: Methadone can have both direct and indirect effects on the kidney. These effects include rhabdomyolysis (leading to acute kidney injury), volumetric changes, renal lipidosis and amyloidosis, kidney growth during pregnancy, and kidney transplant rejection. CONCLUSION: Improved understanding of the effects of methadone on kidney function can promote safer and more confident use of the drug.