IDIOPATHIC INFLAMMATORY MYOPATHIES - OPTIMUM IMMUNOSUPPRESSIVE TREATMENT

The idiopathic inflammatory myopathies include polymyositis and dermat omyositis, which tend to be responsive to drug therapy, and inclusion body myositis, which is often unresponsive or only partially responsiv e to drugs. Corticosteroids are considered the first line treatment of these disorders, and as well as being anti-inflammatory are immunosup pressive when used at dosages above prednisolone 20 mg/day or equivale nt. In those patients who are refractory to corticosteroids, or are pr one to develop complications from corticosteroids, second line drugs s uch as methotrexate, azathioprine or intravenous immunoglobulin should be introduced. These therapies tend to be slow acting, but response o ften occurs in 4 to 6 weeks and allows the dosage of corticosteroid to be reduced more rapidly. In these occasional patients with inflammato ry myopathies that are refractory to corticosteroids and second line a gents, one should consider adding in a third line agent such as cyclos porin, chlorambucil or cyclophosphamide. Although most clinicians woul d use these immunosuppressive drugs singly in combination with cortico steroids, multiple drug therapy should be considered in severe refract ory cases.