[Interaction of cyclosporin and ethambutol-isoniazid]

A 34-year-old patient prophylactically received tuberculostatic treatment with ethambutol and isoniazide after having had an allogenic renal transplant and immunosuppression with methylprednisolone and cyclosporine. The tuberculostatic treatment was discontinued 165 days after the transplantation. The cyclosporine blood level, which was measured daily thereafter, gradually rose from 250 ng/ml to 400 ng/ml. It is possible that enzyme induction due by the tuberculostatic drugs was responsible for the increased breakdown of cyclosporine.