[Effectiveness of tacrolimus in a case of polymyositis].

We report a 57 year-old woman with polymyositis and interstitial pneumonia. With the steroid therapy alone, the decline of creatine kinase was insufficient and muscle strength was not improved. After the addition of tacrolimus 3 mg, serum creatine kinase declined, muscle strength was improved, and the dose of steroid could be tapered very smoothly. There was no remarkable change in the status of the interstitial pneumonia on the chest CT, but the vital capacity was improved. The improvement of the respiratory muscle strength might reduce the respiratory symptom and increase the daily activity in this case. It was possible that dose of steroid was tapered early with tacrolimus, and the side effect which accompanies long-term medication of steroids could be avoided. In polymyositis, tacrolimus is very useful medicine in the steroid-resistant case or in the case suffering from the side effect of steroids. There is possibility that tacrolimus becomes one of the choices of the treatment of polymyositis.