Tacrolimus hydrate (FK506): therapeutic effects and selection of responders in the treatment of myasthenia gravis

Tacrolimus hydrate (FK506) reduces myasthenic symptoms due to its immunosuppressive properties. We studied the therapeutic effects of FK506 and noted improvement in 7 of 13 myasthenic patients on the clinical muscle test (myasthenia gravis, MG score). Two other patients with relapsing ocular symptoms improved. We also examined patient sensitivity to FK506, but could not predict such sensitivity before FK506 treatment in the present study.