Pharmacological treatment of nephrotic syndrome.

In the "minimal change" nephrotic syndrome (MCNS), steroids induce remissions in most cases (93% in children and 81% in adults). Response occurs in an average time of 11 days in children but may take up to 16 weeks in adults. The dose of prednisone is 60 mg/m(2)/day (maximum 80 mg/day) given usually for 4 weeks and then reduced to 40 mg/m(2) on alternate days for a few weeks. The medication may be discontinued abruptly at the end of the course of treatment. Children who do not respond to prednisone should be biopsied. Those whose biopsy shows minimal changes may have a remission with more prolonged alternate day treatment, or may need cyclophosphamide or cyclosporine. Relapses of nephrotic syndrome are common and usually respond to steroids given daily until remission, then on alternate days for 4 weeks. In adults prednisone on alternate days for 1 year after the presenting attack decreases the risk of relapse. Toxicity is a problem only in steroid-dependent patients who may require other drugs. Cyclophosphamide (2-3 mg/kg/day) and chlorambucil (0.15 mg/kg/day) for 8-12 weeks induce long-term remissions in 25-70% of children and are also beneficial in adults. The effectiveness of cyclophosphamide in steroid-resistant MCNS is limited to bringing about a faster remission. In children with MCNS who are initially steroid-responsive and later become resistant, cyclophosphamide usually induces a remission and restores steroid responsiveness. The toxicity of cyclophosphamide and chlorambucil in MCNS has generally been mild and reversible. It includes bone marrow depression, hemorrhagic cystitis, some hair loss, infertility and, extremely rarely, oncogenesis. The risk of gonadal toxicity is minimized with total doses below 200 mg/kg for cyclophosphamide and 7-10 mg/kg for chlorambucil. Seizures have been reported in 8% of children treated with chlorambucil. Cyclosporine (6 mg/kg/day initially) produces complete remissions in 85% of children and 79% of adults with steroid dependence and in 67% of children and 61% of adults with steroid resistance. Levamisole may be helpful in steroid-dependent cases, but data about its efficacy are conflicting. Cyclosporine and levamisole usually do not induce permanent remissions.