Lowers Vitamin C absorption Anticonvulsants Dilantin, phenobarbital Increase the risk of anemia and nerve problems due to deficiency of folalte and other B vitamins. Tricyclics Many foods, especially legumes, meat, fish, and foods high in Vitamin C, reduce absorption of the drugs Antihypertensives, Heart Medications ACE inhibitors Take on an empty stomach to improve the absorption of the drugs. Alpha blockers Take with liquid or food to avoid excessive drop in blood pressure. Antiarrhythmic drugs Avoid caffeine, which increases the risk of irregular heartbeat. Digitalis Avoid taking with milk and high fiber foods, which reduce absorption, increases potassium loss.
Diuretics Increase the risk of potassium deficiency.
Unless a doctor advises otherwise, don't take diuretics with potassium supplements or salt substitutes, which can cause potassium overload. Asthma Drugs Pseudoephedrine Avoid caffeine, which increase feelings of anxiety and nervousness. Theophylline Charbroiled foods and high protein diet reduce absorption. Caffeine increases the risk of drug toxicity. Avoid fatty foods, which decrease the drug's efficacy in lowering cholesterol.