Rifampin is an enzymatic inducer known to increase steroid metabolism. We studied two patients with giant cell arteritis in whom rifampin caused nonresponsiveness to prednisone treatment. A prednisolone pharmacokinetics study was done. When rifampin-prednisone treatment must be used in giant cell arteritis, we propose increasing the prednisone dosage to 2 mg/kg per day.
(Arch Intern Med. 1994;154:1521-1524)