β-carotene: May interfere w/ healing following angioplasty. Vit C: Risk of kidney stone formation in patients w/ kidney disease. Vit E: Vit K deficiency, bleeding propensity or lesions eg, bleeding peptic ulcers, hemophilia. Pregnancy & lactation.
May decrease effectiveness of medications used to lower cholesterol & niacin. Vit E: May increase chances of bruising & bleeding w/ medications that also slow blood clotting. Vit C: May increase absorption of medications containing Al eg, phosphate binders.