Increased risk of renal adverse effects w/ acetaminophen, other nephrotoxic medications including gold compd. Increased risk of GI effects w/ alcohol, corticosteroids, glucocorticoid or corticotropin, K supplements. Inhibited platelet aggregation w/ coumarin- or indandione-derivative anticoagulants, heparin, thrombolytics; cefamandole, cefoperazone, cefotetan, plicamycin or valproic acid; other platelet aggregation inhibitors. Increased &/or decreased effect of oral antidiabetic agents or insulin. Reduced or reversed antihypertensive effects of diuretics & antihypertensives. Increased risk of GI toxicity w/ aspirin or other NSAIDs; colchicine; sulfinpyrazone. Increased leukopenic &/or thrombocytopenic effects of bone marrow depressants. Increased plasma conc of cyclosporine. Increased serum digoxin, lithium, methotrexate conc. Additive photosensitising effects w/ other photosensitising medications. Increased serum conc by probenecid.