- Concomitant administration of other potentially hepatotoxic drugs(Methotrexate, Phenytoin, phenobarbitone, carbamazepine ,valproate Atenolol, labetalol, Salicylates , allopurinol, quinine, quinidine, fluconazole, cimetidine, ethionamide, verapamil, probenecid, TCA, halothane)