Increased risk/intensity of bleeding w/ oral anticoagulants, glycoprotein IIb/IIIa inhibitors, heparin, thrombolytics, NSAIDs including Cox-2 inhibitors, SSRIs. Increased occult GI blood loss w/ naproxen. Reduced effect of ASA w/ metamizole. Clopidogrel: Reduced levels of the active metabolite of clopidogrel w/ strong or moderate CYP2C19 inhibitors (eg, omeprazole & esomeprazole, fluvoxamine, fluoxetine, moclobemide, voriconazole, fluconazole, ticlopidine, carbamazepine, efavirenz). Decreased exposure w/ proton pump inhibitors eg, omeprazole, esomeprazole. Increased exposure of CYP2C8 substrate medicinal products eg, repaglinide & paclitaxel. ASA: May inhibit the effect of uricosuric agents (eg, benzbromarone, probenecid, sulfinpyrazone). Can inhibit renal clearance of methotrexate. Increased risk of renal failure w/ tenofovir disoproxil fumarate. Increased serum levels of total & free valproic acid. Do not give salicylates for an interval of 6 wk after receiving varicella vaccine. Increased risk of metabolic acidosis w/ acetazolamide. Increased risk of GI ulceration, perforation & haemorrhage w/ nicorandil. Increased risk of GI injury w/ alcohol.