Vitamin C Interactions
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The following are the medications and supplements that are more likely to cause a reaction with vitamin C supplements:
- Aminosalicylic acid
People taking aminosalicylic acid medication for tuberculosis must not take large doses of vitamin C as this increases the risk that the drug will form crystals in the urine, which can be painful and dangerous. - Antacids containing aluminium
People taking aluminium-containing antacids should not take high doses of vitamin C supplements as this combination may increase adverse effects associated with the antacids containing aluminium. - Anticholinergics
People taking anticholinergic medications should avoid taking vitamin C supplements as the vitamin C as they can reduce the effectiveness of the anticholinergic medications. - Anticoagulants
People taking anticoagulant medications should avoid taking vitamin C supplements as the vitamin C as they can reduce the effectiveness of the anticoagulant medications. - Aspirin
People taking aspirin may need to be supplemented with vitamin C, especially if they take aspirin long term (which many people at risk of heart disease take as a blood thinner). People that take aspirin as a blood thinner should seek the advice of their doctor to determine how much vitamin C supplementation is required for their individual circumstances. - Barbituates
People taking barbituates should not take vitamin C at the same time, as this combination will increase the effect of the Barbituates medications and decrease the effectiveness of the vitamin C. - Calcium
People taking calcium supplements can take vitamin C supplements at the same time as the vitamin C will help the body better absorb the calcium. - Copper
People taking copper supplements are advised not to take high levels of vitamin C supplements as they can reduce the absorption of copper. People taking copper supplements should only take the recommended daily intake (up to the tolerable upper limit, but only for a short duration) to avoid this. - Cyclophosphamide
People taking cyclophosphamide, an anti-cancer chemotherapy medication may find benefit from taking vitamin C supplements, such as a reduction in the likelihood and/or severity of potential side effects caused by this medication.
Vitamin C interacts with a number of medications and supplements
- Deoxycorticosteroids
People taking corticosteroids may have lower levels of vitamin C, as these drugs cause higher urinary excretion of vitamin C and so supplementation may be required. - Fluorouracil
People taking fluorouracil, an anti-cancer chemotherapy medication may find benefit from taking vitamin C supplements, such as a reduction in the likelihood and/or severity of potential side effects caused by this medication. - Iron
People taking iron supplements are advised to take some vitamin C supplements to help the body better absorb the iron. - Oestrogen
Women taking oestrogen or oral contraceptives may decrease the absorption and effectiveness of vitamin C from foods. If vitamin C supplements are taken with oral contraceptives or oestrogens, this combination can increase blood levels of ethinyl estradiol. - Quinidine
People taking quinidine should avoid taking vitamin C supplements as the vitamin C can decrease the effectiveness of the quinidine. - Salicylates
People taking salicylates may need to be supplemented with vitamin C. This medication can reduce the absorption of vitamin C and this may lead to a deficiency if not rectified. - Sulfa drugs
People taking sulfa drugs may need to be supplemented with vitamin C. This medication can reduce the absorption of vitamin C and this may lead to a deficiency if not rectified. The sulfa drugs may also cause kidney stones especially if taken long term. - Tetracyclines
People taking tetracyclines may need to be supplemented with vitamin C. This medication can reduce the absorption of vitamin C and this may lead to a deficiency if not rectified. - Vitamin B12 (cobalamin)
Really high doses of vitamin C can decrease the absorption and effectiveness of vitamin B12 (cobalamin) from foods and so supplementation may be needed.