Increased frequency of skin rash w/ ampicillin/amoxicillin. May prolong the elimination t
½ of anticoagulants (eg, warfarin & other coumarin derivatives); increase plasma conc of ciclosporin; inhibit the oxidative metabolism of azathioprine & mercaptopurine, hepatic oxidation of phenytoin & metabolism of theophylline. Risk of hypersensitivity reactions eg, SJS w/ ACE inhibitors eg, captopril. Enhanced hypoglycemic effect w/ chlorpropamide (when renal function is poor). Enhanced bone marrow suppression w/ cyclophosphamide & other cytotoxic agents. Increased risk of hypersensitivity w/ thiazides & related diuretics especially in patients w/ renal impairment. Doubled plasma didanosine C
max & AUC values (w/ allopurinol 300 mg daily). Excretion may be accelerated by drugs w/ uricosuric activity eg, probenecid or large doses of salicylate. Increased plasma t
½ of vidarabine.