Vit A: Increased risk of bleeding w/ anticoagulants (eg, warfarin). Potential additive side effects w/ retinoid (eg, etretinate, isotretinoin, tretinoin). Increased risk of pseudomotor cerebri w/ minocycline. Increased serum levels w/ statins. Vit C: Increased risk of Al toxicity w/ antacids, specifically in patients w/ renal insufficiency. Concomitant use w/ aspirin may increase urinary excretion of ascorbic acid & decrease excretion of aspirin. May interfere w/ alcohol-disulfiram reaction. Decreased fluphenazine plasma level. May accelerate excretion of mexiletine. Increases apparent t
½ of paracetamol. Reduced blood levels w/ OCs containing estrogens. Decreased anticoagulant effect of warfarin. May result in altered excretion of other drugs. Vit E: May have anti-vit K effects; hemorrhage in concomitant w/ anticoagulants (eg, warfarin). May potentiate the effects of antiplatelets (eg, aspirin, clopidogrel, ticlopidine) & herbs w/ antithrombotic activity eg, garlic & ginkgo. Zn: Decreases absorption of antibiotics (eg, cephalosporins, quinolones, tetracyclines) & bisphosphonates (eg, alendronate, etidronate, risedronate). Additive effects w/ cholesterol medicines. Inhibits absorption of Cu & Fe.