Cautions and interactions for vitamin B complex products

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.]

Vitamin B3 supplements may affect the 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.

It is recommended to take supplements containing calcium, magnesium, zinc or iron away from prescription medications. Separate by at least two hours.