The treatment of minimal change nephrotic syndrome: lessons learned from multicentre co-operative studies.

Minimal change nephrotic syndrome (MCNS) is the most frequent type of nephrotic syndrome in childhood. Treatment aims to induce remission, prevent relapses and avoid side-effects. MCNS is responsive to immunosuppressive therapy with glucocorticosteroids, alkylating drugs and cyclosporine A. From results of multicentre controlled studies it became evident that the initial treatment with prednisone should be intensive, i.e. for 12 weeks, in order to reduce the risk of subsequent relapses. Treatment of relapses should be standardized in order to categorize the patient's disease for further treatment. In case "frequent relapsers" develop signs of steroid-toxicity, they should be treated with alkylating drugs: frequent relapsers without steroid dependency with cyclophosphamide or chlorambucil for 8 weeks, steroid-dependent cases with cyclophosphamide for 12 weeks. If frequent relapses re-occur after cytotoxic drug therapy, treatment with cyclosporine A should be considered. Starting dose is 100-150 mg/m2 per day and needs to be adjusted to the whole blood trough level. Treatment with cyclosporine A must be strictly controlled in order to avoid chronic nephrotoxicity. Cyclosporine A does not cure MCNS. It is only effective as long as it is administered; therefore long-lasting treatment is necessary in most cases.