Seasonal Support Interactions

Aspirin and Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) - Very limited research suggests that vitamin C may protect the stomach and intestines against injury from NSAIDs such as ibuoprofen. On the other hand, high doses of vitamin C (equal to or greater than 500 mg per day) may raise the blood levels of aspirin and other acidic medications.

Acetominophen - Vitamin C may decrease excretion of acetaminophen (a medication sold over the counter for pain and headache) in the urine, which may increase blood levels of this medication.

Diuretics, Loop - Animal studies suggest that vitamin C may amplify the effects of furosemide, which belongs to a class of medications known as loop diuretics.

Beta-blockers for high blood pressure - Vitamin C may decrease the absorption of propranolol, a medication that belongs to a class known as beta-blockers used for high blood pressure and other heart-related conditions. If taking vitamin C and a beta-blocker, therefore, it is best to take them at different times of the day.

Cyclosporine - Cyclosporine, a medication used for the treatment of cancer, may reduce blood levels of vitamin C.

Nitrate Medications for heart disease - The combination of vitamin C with nitroglycerin, isosorbide dinitrate, or isosorbide mononitrate reduces the occurrence of nitrate tolerance. Nitrate tolerance is when the body builds up a tolerance to the medicine so that it no longer has its desired effect. People taking nitrate-containing medications generally follow a 12 hours on, 12 hours off schedule to avoid this tolerance. Studies suggest that taking vitamin C along with nitrate medications may reduce the development of this tolerance.

Tetracycline - There is some evidence that taking vitamin C with the antibiotic tetracycline may increase the levels of this medication.

Warfarin - There have been rare case reports of vitamin C interfering with the effectiveness of this blood thinning medication. In recent follow up studies, no such association has been found with doses of vitamin C up to 1,000 mg per day. Because of these much earlier reports, however, some conservative clinicians suggest not exceeding RDA values of vitamin C (see earlier section entitled How To Take It). Whether taking recommended dietary amounts or larger quantities of vitamin C, anyone on warfarin must have their bleeding time measured regularly and followed closely using a value called an INR, measured at your doctor's office. If you take this blood thinner, any time you make a change to your diet, medications, or supplements, you must notify your physician.  

Blood Pressure Medications, ACE Inhibitors - A class of medications called ACE Inhibitors, such as captopril and enalpril, used for high blood pressure may deplete zinc stores.

Antibiotics - Zinc may decrease the absorption of oral quinolones, a class of antibiotics that includes ciprofloxacin, norfloxacin, ofloxacin, and levofloxacin, as well as tetracycline antibiotics (including tetracycline, doxycycline, and minocycline).

Hormone Replacement Therapy (HRT) - HRT, consisting of estrogen and progesterone derivatives may reduce loss of zinc in the urine, particularly in women with osteoporosis.

Hydralazine - There has been at least one report of an interaction between zinc and hydralazine, a medication used to treat high blood pressure, which resulted in a lupus-erythematosus-like syndrome (characterized by a facial butterfly rash, fever, leg and mouth ulcers, and abdominal distress).

Immunosuppressant Medications - Since zinc supports immune function, it should not be taken with corticosteroids, cyclosporine, or other medications intended to suppress the immune system.

Nonsteroidal Anti-inflammatory Drugs (NSAIDs) - Zinc interacts with NSAIDs and could reduce the absorption and effectiveness of these medications. Examples of NSAIDs, which help to reduce pain and inflammation, include ibuprofen, naprosyn, piroxicam, and indomethacin.

Penicillamine - This medication, used to treat Wilson's disease (excessive amounts of copper that accumulate in the brain, liver, kidney, and eyes) and rheumatoid arthritis, decreases zinc levels.  

Antibiotics - In a clinical study, the combination of bromelain and amoxicillin increased the levels of this antibiotic in the blood. Some studies suggest that bromelain may increase the body's ability to absorb tetracycline, but results of other studies have been conflicting. Until studies confirm these results, it would be wise to avoid combining bromelain and tetracycline.

Studies with bromelain and tetracycline have produced mixed results. Some research suggests that bromelain increases levels of tetracycline in the body, while others indicate that it may cause more of the antibiotic to be excreted in the urine.

Blood-thinning Medications - People taking aspirin, warfarin, or other medications that thin the blood should use bromelain with extreme caution because of a possible risk of bleeding when used together.  

Antibiotics, Tetracycline - Niacin should not be taken at the same time as the antibiotic tetracycline because it interferes with the absorption and effectiveness of this medication. Niacin either alone or in combination with other B vitamins should be taken at different times from tetracycline. (All vitamin B complex supplements act in this way and should therefore be taken at different times from tetracycline.)

Aspirin - Taking aspirin before taking niacin may reduce flushing associated with this vitamin. This should only be done under the advice of a healthcare practitioner.

Blood Pressure Medications, Alpha-blockers - When niacin is taken with certain blood pressure medications known as alpha-blockers (such as prazosin, doxazosin, and guanabenz), the likelihood of side effects from these medications is increased.

Cholesterol-lowering Medications - Niacin binds bile-acid sequestrants (cholesterol-lowering medications such as colestipol, colesevelam, and cholestyramine) and may decrease their effectiveness. For this reason, niacin and these medications should be taken at different times of the day.

As described earlier, recent scientific evidence suggests that taking niacin with simvastatin (a drug that belongs to a class of cholesterol-lowering medications known as HMG-CoA reductase inhibitors or statins including atorvastatin and lovastatin as well), appears to slow down the progression of heart disease. However, the combination may also increases the likelihood for serious side effects, such as muscle inflammation or liver damage.

Diabetes Medications - People taking insulin, metformin, glyburide, glipizide, or other medications used to treat high blood sugar levels should monitor their blood sugar levels closely when taking niacin supplements.

Isoniazid (INH) - INH, a medication used to treat tuberculosis, may deplete levels of niacin and cause a deficiency.

Nicotine Patches - The use of nicotine patches with niacin may worsen or increase the risk of flushing reactions associated with this vitamin when used medicinally.  

Econazole - Echinacea may be useful in combination with econazole, an antifungal agent used to treat yeast infections (such as athlete's foot). When echinacea is used together with econazole, recurrence rates of these infections may be reduced.

Immunosuppressants - Immunosuppressants refers to a group of medications that are used for two main purposes -- treat cancer and suppress the immune system following organ transplant so that the new organ is not rejected. Because echinacea can enhance immune function, it is not advisable to use the herb with medications in this class, especially for organ transplant.

In terms of cancer treatment, however, a couple of test tube studies imply that echinacea may prove useful when used in conjunction with cyclophosphamide, one medication in this class. The idea is that using echinacea with this or other chemotherapy agents that act as immunosuppressants, may allow the cancer-fighting medicines to kill the tumors while the immune system continues to be protected. If this theory proves to be correct, then, echinacea could possibly prevent many of the untoward side effects of chemotherapy.