Vitamin C Risks, Warnings, and Complications

Precautions Before Starting Vitamin C

Tell your doctor if you have ever had an allergic reaction to vitamin C, any of the active or inactive ingredients in vitamin C formulations, or any other medications. Your pharmacy can give you a list of ingredients.

Give your doctor and pharmacist a complete list of your medications, including prescription medications, over-the-counter medicines, vitamins, dietary supplements, and herbal remedies. This can help avoid possible drug interactions between vitamin C and your other medicines.

Vitamin C may not be right for people with certain medical conditions, such as chronic kidney disease, G6PD deficiency, hereditary hemochromatosis, thalassemia, and sickle cell disease. Give your doctor a complete medical history before starting any dietary supplements.

Tell your health care professional if you are pregnant, could be pregnant, plan to get pregnant, or are breast-feeding.

Precautions During Use of Vitamin C

Keep all your medical and lab appointments. Follow the dosing instructions on the prescription label or package label.

Tell your doctor if you become pregnant while on this medication.

Vitamin C Drug Interactions

Other drugs can affect how vitamin C works. Possible interactions with certain medications can increase the risk of severe adverse effects. Some of the medications that can have interactions with vitamin C include:

• Aluminum-containing medications, such as phosphate binders
• Chemotherapy drugs
• Estrogen (oral contraceptives or hormone replacement therapy)
• Antiviral drugs called protease inhibitors used to treat HIV
• Cholesterol-lowering drugs such as statins and niacin
• Anticoagulants (blood thinners) such as warfarin (Coumadin, Jantoven)

Give your doctor or pharmacist a complete list of your medications, including prescription drugs, nonprescription drugs, dietary supplements, and herbal remedies. Also, tell your healthcare professional if you smoke, drink alcohol, or use recreational drugs because some of these substances can cause serious health complications when used with prescription medications, over-the-counter medicines, and dietary supplements.