Cautions & Interactions for multivitamin and mineral products
- Vitamin B3 supplements may affect the way body’s control of blood glucose levels and may require adjustments to diabetes medications.
- Vitamin B3 supplements may improve the therapeutic effects of lipid-lowering drugs (eg cholestyramine, colestipol) or statins.
- Concomitant use of vitamin B6 supplements and amiodarone may lead to increased risk of drug-induced photosensitivity.
- Vitamin B6 supplements may affect the way anticonvulsants or levodopa work in the body.
- Use of anticonvulsants, methotrexate, sulfasalazine, trimethorprim, NSAIDS, the oral contraceptive pill, antacids, H2 antagonists and proton pump inhibitors may reduce levels of folic acid in the body. Supplements containing folic acid may be beneficial. Consult your healthcare professionals as folic acid supplementation may also affect the efficacy of some of these medications.
- Use of colchicine, proton pump inhibitors, H2 antagonists, carbamazepine or metformin may reduce levels of vitamin B12 in the body. Supplements containing vitamin B12 may be beneficial.
- Use of vitamin C supplements should be stopped prior to some laboratory testing procedures as results may be affected.
- Vitamin C may increase the absorption of aluminium from aluminium-based antacids. Separate by at least two hours.
- Vitamin D supplements may reduce the effectiveness of calcium channel blockers and may increase the risk of hypercalcaemia in individuals taking thiazide diuretics.
- Use of high doses of vitamin E should be stopped at least two weeks prior to surgery.
- The use of some prescription medications may reduce levels of some B vitamins and vitamins C and E. A broad spectrum B complex or multivitamin supplement may be beneficial. [Drugs include: the oral contraceptive pill, tricyclics antidepressants, diuretic medications, antituberculosis drugs, theophylline, penicillamine, gastric acid inhibitors, lipid-lowering drugs, carbamazepine.]
- Ginseng may affect the way warfarin, digoxin, hypoglycaemic medications and phenelzine work in the body.
- Supplements containing Korean ginseng should be used with caution in individuals with hypertension.
- Kelp may affect the way thyroxine works due to iodine content.
- Supplements containing calcium, magnesium, zinc or iron may affect the absorption or efficacy of some prescription medications. Separate by at least two hours.
- Tea and coffee may also impair the absorption of iron so take iron-containing supplements at least two hours away from consuming caffeinated beverages.
- Concomitant use of vitamin E-, grape seed extract- or Siberian ginseng-containing supplements and warfarin or other medications that affect blood clotting (including aspirin) may lead to an increased risk of bleeding.
- Concomitant use of vitamin E supplements and cisplatin may reduce drug-induced neurotoxicity effects.
- Supplements containing glucosamine may affect the way warfarin or hypoglycaemic medications work in the body.
It is recommended to consult your healthcare professional before taking natural health supplements in conjunction with prescription medications.
