The effect of levamisole on kidney function in children with steroid-sensitive nephrotic syndrome

BACKGROUND: Levamisole is frequently used as a steroid-sparing agent in children with steroid-sensitive nephrotic syndrome. Side effects, such as neutropenia, gastro-intestinal upset and skin rash, have been reported. We noted an increase in creatinine in some of our patients, but literature on the effect of levamisole on kidney function is lacking. METHODS: A retrospective cohort study was conducted, including patients 1–18 years of age, treated for steroid-sensitive nephrotic syndrome with levamisole at Great Ormond Street Hospital for Children between January 2010 and January 2020. Data was collected on clinical observations and serum creatinine values before, during and after treatment. eGFR was calculated using the Schwartz equation. RESULTS: In total, 75 children were included in the analysis. The median duration of treatment was 19 (IQR 12–27) months. The median estimated GFR was 134 (IQR 119–160), 101 (IQR 91–113) and 116 (IQR 106–153) ml/min/1.73 m(2), respectively, before, during and after treatment with levamisole. The difference between eGFR before and after treatment compared with during treatment was statically significant (P < 0.0001). During the treatment period, the eGFR decrease was not progressive. The median levamisole dose was 2.5 (IQR 2.3–2.6) mg/kg on alternate days, and the dose was not correlated with the decrease in eGFR (r = 0.07, 95% CI − 0.22 to 0.35). CONCLUSION: Levamisole significantly decreases eGFR. However, this decrease is not progressive or irreversible and would not be an indication to discontinue the treatment.