Pharmacology: Drugs Effects and Precautions

Antibiotics

• Cephalosporins should be taken on an empty stomach to speed up absorption.
• Erythromycin should not be taken with fruit juice or wine, as they decrease the drug's effectiveness.
• Sulfa drugs increase the risk of vitamin B12 deficiency.
• Tetracycline's effectiveness is reduced by dairy products, and it also lowers vitamin C absorption.

Anticonvulsants

• Dilantin and phenobarbital increase the risk of anemia and nerve problems due to a deficiency in folate and other B vitamins.

Antidepressants

• Fluoxetine reduces appetite and can lead to excessive weight loss.
• Lithium's effectiveness is affected by salt intake: a low-salt diet increases the risk of lithium toxicity, while excessive salt reduces the drug's efficacy.
• Monoamine oxidase (MAO) inhibitors interact with foods high in tyramine (e.g., aged cheeses, processed meats, legumes, wine, and beer), which can bring on a hypertensive crisis.
• Tricyclics have reduced absorption when taken with certain foods, such as legumes, meat, fish, and foods high in vitamin C.

Antihypertensives and Heart Medications

• Angiotensin-converting enzyme (ACE) inhibitors should be taken on an empty stomach to improve absorption.
• Alpha-blockers should be taken with liquid or food to avoid an excessive drop in blood pressure.
• Antiarrhythmic drugs interact with caffeine, which increases the risk of an irregular heartbeat.
• Beta-blockers should be taken on an empty stomach, as food (especially meat) increases the drug's effects and can cause dizziness and low blood pressure.
• Digitalis should be taken with caution, as milk and high-fiber foods reduce absorption, and it increases potassium loss.
• Diuretics increase the risk of potassium deficiency.
• Potassium-sparing diuretics should not be taken with potassium supplements or salt substitutes, unless advised by a doctor, to avoid potassium overload.
• Thiazide diuretics increase the reaction to MSG.

Asthma Drugs

• Pseudoephedrine interacts with caffeine, which increases feelings of anxiety and nervousness.
• Theophylline's absorption is reduced by charbroiled foods and a high-protein diet, and caffeine increases the risk of drug toxicity.

Cholesterol-Lowering Drugs

• Cholestyramine increases the excretion of folate and vitamins A, D, E, and K.
• Gemfibrozil's efficacy is decreased by fatty foods.

Heartburn and Ulcer Medications

• Antacids interfere with the absorption of many minerals and should be taken 1 hour after eating for maximum benefit.
• Cimetidine, famotidine, and sucralfate interact with high-protein foods, caffeine, and other items that increase stomach acidity.

Hormone Preparations

• Oral contraceptives reduce the absorption of folate, vitamin B6, and other nutrients, and increase the intake of foods high in these nutrients to avoid deficiencies.
• Salty foods increase fluid retention when taking oral contraceptives.
• Steroids also increase fluid retention with salty foods, and require increased intake of foods high in calcium, vitamin K, potassium, and protein to avoid deficiencies.

Thyroid Drugs

• Iodine-rich foods may lower the drug's efficacy.

Laxatives

• Mineral oils can cause a deficiency of vitamins A, D, E, and K if overused.

Painkillers

• Aspirin and stronger nonsteroidal anti-inflammatory drugs (NSAIDs) should be taken with food to lower the risk of gastrointestinal irritation, and should not be taken with alcohol, which increases the risk of bleeding.