Drug & Supplement Interaction

Physicians prescribe drugs to treat or prevent diseases, disorders and medical conditions. People also often choose to take nutritional supplements for the same reason. However, nutritional supplements can effect the safety and efficacy of certain medications, and some medications can effect the way your body uses supplements. Interactions between drugs and nutritional supplements can cause dangerous side effects or be fatal, especially as you increase the number and types of drugs you take. Upon receiving your prescription, always consult your doctor and pharmacist about the potential interactions that can occur between drugs and supplements.

Orlistat and Fat Soluble Vitamins

Orlistat is the active pharmaceutical ingredient in Xenical and Alli, prescription and over-the-counter weight loss drugs, respectively. Orlistat helps you lose weight by inhibiting a certain amount of fat you absorb from food. As a result of this mechanism of action, the drugs may also inhibit absorption of fat soluble vitamins, which include vitamins A, D, E and K, from both food and supplements, potentially causing a vitamin deficiency. The National Institute of Diabetes and Digestive and Kidney Diseases recommends you take fat soluble vitamin supplements at least 2 hours before or after taking orlistat.

Steroid Drugs and Vitamin D

Steroids, particularly corticosteroids, are medications physicians prescribe to treat patients experiencing inflammation from rheumatoid arthritis, lupus erythematosus and other types of inflammatory conditions. Steriods are also prescribed for patients who undergo organ transplants. Certain corticosteroids, such as prednisone, can impair the normal functioning of vitamin D in bone growth and cause bone loss and osteoporosis. Taking anabolic steroids, which drugs used to enhance athletic performance, with vitamin D supplements may impair kidney function. Research by scientists at General Hospital of Fortaleza in Brazil and published in "International Urology and Nephrology" in 2009 found that taking anabolic steroids and vitamin D supplements can cause kidney dysfunction.

Tetracycline Antibiotics and Vitamin A

Tetracycline is a broad-spectrum antibiotic physicians prescribe to treat bacterial infections of the respiratory tract, urinary tract, intestines, sinuses, middle ear and skin, including moderately severe acne and rosacea and other conditions, such as Gonorrhea, Lyme disease, Rocky Mountain spotted fever and typhus. Tetracycline medications include demeclocycline and minocycline. Taking high doses of vitamin A with tetracyclines may increase your risk of intracranial hypertension, which is characterized by fluid pressure in your brain.

Oxycodone and St John's Wort

Taking supplements containing St John's Wort may reduce the effectiveness of oxycodone in treating pain. St John's Wort is an herb that is effective in treating mild to moderate depression. Oxycodone is a narcotic prescription drug physicians prescribe to treat patients with moderate to severe pain. Research by scientists at the University of Turku in Finland and published in the "European Journal of Pain" in 2010 found that St John's Wort greatly reduces blood concentrations of oxycodone. Patients who take both substances report less effectiveness in relief of pain compared to taking oxycodone alone.