Vit: Drugs w/ same content, NSAIDs, anticoagulants, cyclosporine, fluorouracil, insulin, phenytoin, HMG-CoA reductase inhibitors, MTX, milk, Al & Cu prep, phenobarb & levodopa. Fe sulfate: Antacids, chloramphenicol, levodopa, levothyroxine, penicillamine, quinolones, cefdinir, dimercaprol, H
2 receptor antagonists, PPIs, tetracycline, & dairy products. Ca: Increases urinary excretion w/ high Na & protein intake. Reduced absorption w/ caffeine & alcohol. Reduces therapeutic effect of Ca-channel blockers (eg, nifedipine & amlodipine). Decreases absorption of quinolones, levothyroxine, phenytoin & tetracycline.