font size
A
A
A

Vitamin C (Ascorbic Acid)

IN THIS ARTICLE

Are there any interactions with medications?



Aluminum
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Aluminum is found in most antacids. Vitamin C can increase how much aluminum the body absorbs. However, it is not clear if this interaction is a big concern. Take vitamin C two hours before or four hours after antacids.



Estrogens
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

The body breaks down estrogens to get rid of them. Vitamin C might decrease how quickly the body gets rid of estrogens. Taking vitamin C along with estrogens might increase the effects and side effects of estrogens.



Fluphenazine (Prolixin)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Large amounts of vitamin C might decrease how much fluphenazine (Prolixin) is in the body. Taking vitamin C along with fluphenazine (Prolixin) might decrease the effectiveness of fluphenazine (Prolixin).



Indinavir (Crixivan)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Indinavir (Crixivan) is a medication used for HIV/AIDS. Taking large amounts of vitamin C along with indinavir (Crixivan) might decrease how much of indinavir (Crixivan) stays in the body. It's not clear if this interaction is a big concern.



Medications for cancer (Chemotherapy)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Vitamin C is an antioxidant. There is some concern that antioxidants might decrease the effectiveness of some medications used for cancers. But it is too soon to know if this interaction occurs.



Medications used for lowering cholesterol (Statins)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Taking vitamin C, beta-carotene, selenium, and vitamin E together might decrease the effectiveness of some medications used for lowering cholesterol. It is not known if vitamin C alone decreases the effectiveness of some medications used for lowering cholesterol.

Some medications used for lowering cholesterol include atorvastatin (Lipitor), fluvastatin (Lescol), lovastatin (Mevacor), and pravastatin (Pravachol).



Niacin
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Taking vitamin C along with vitamin E, beta-carotene, and selenium might decrease some of the helpful effects of niacin. Niacin can increase the good cholesterol. Taking vitamin C along with these other vitamins might decrease the effectiveness of niacin for increasing good cholesterol.



Pentobarbital
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Taking vitamin C with pentobarbital might increase the sedative effects of pentobarbital.



Warfarin (Coumadin)
Interaction Rating: Moderate Be cautious with this combination.
Talk with your health provider.

Warfarin (Coumadin) is used to slow blood clotting. Large amounts of vitamin C might decrease the effectiveness of warfarin (Coumadin). Decreasing the effectiveness of warfarin (Coumadin) might increase the risk of clotting. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.



Acetaminophen (Tylenol, others)
Interaction Rating: Minor Be cautious with this combination.
Talk with your health provider.

The body breaks down acetaminophen (Tylenol, others) to get rid of it. Large amounts of vitamin C can decrease how quickly the body breaks down acetaminophen. It is not clear exactly when or if this interaction is a big concern.



Aspirin
Interaction Rating: Minor Be cautious with this combination.
Talk with your health provider.

Aspirin is removed by the body through the kidneys and in the urine. Some scientists have raised concern that vitamin C might decrease how the body removes aspirin and could potentially increase the amount of aspirin in the body. There is concern that this could increase the chance of aspirin-related side effects. However, some research suggests that this is not an important concern and that vitamin C does not interact in a meaningful way with aspirin. Some research actually suggests that taking vitamin C with buffered aspirin might decrease the stomach irritation caused by aspirin. More evidence is needed about this possible benefit.



Choline Magnesium Trisalicylate (Trilisate)
Interaction Rating: Minor Be cautious with this combination.
Talk with your health provider.

Vitamin C might decrease how quickly the body gets rid of choline magnesium trisalicylate (Trilisate). It is not clear if this interaction is a big concern.



Medications used for HIV/AIDS (Protease Inhibitors)
Interaction Rating: Minor Be cautious with this combination.
Talk with your health provider.

Taking large doses of vitamin C might reduce how much of some medications used for HIV/AIDS stays in the body. This could decrease the effectiveness of some medications used for HIV/AIDS.

Some of these medications used for HIV/AIDS include amprenavir (Agenerase), nelfinavir (Viracept), ritonavir (Norvir), and saquinavir (Fortovase, Invirase).



Nicardipine (Cardene)
Interaction Rating: Minor Be cautious with this combination.
Talk with your health provider.

Vitamin C is taken up by cells. Taking nicardipine (Cardene) along with vitamin C might decrease how much vitamin C is taken in by cells. The significance of this interaction is not clear.



Nifedipine
Interaction Rating: Minor Be cautious with this combination.
Talk with your health provider.

Vitamin C is taken up by cells. Taking nifedipine (Adalat, Procardia) along with vitamin C might decrease how much vitamin C is taken in by cells. The significance of this interaction is not clear.



Salsalate (Disalcid)
Interaction Rating: Minor Be cautious with this combination.
Talk with your health provider.

Vitamin C might decrease how quickly the body gets rid of salsalate (Disalcid). Taking vitamin C along with salsalate (Disalcid) might cause too much salsalate (Disalcid) in the body, and increase the effects and side effects of salsalate.

Dosing considerations for Vitamin C.

The following doses have been studied in scientific research:

BY MOUTH:
  • General: The daily recommended dietary allowances (RDAs) are: 90 mg for men and 75 mg for women; Pregnancy and Lactation: age 18 or younger, 115 mg; ages 19 to 50 years 120 mg. People who use tobacco should take an additional 35 mg per day. Do not take more than the following amounts of vitamin C: 1800 mg per day for adolescents and pregnant and breast-feeding women 14 to 18 years, and 2000 mg per day for adults and pregnant and lactating women.
  • For vitamin C deficiency: 100-250 mg once or twice daily for several days for scurvy.
  • For empting the colon before a colonoscopy: 2 liters of solution containing polyethylene glycol and vitamin C is used the evening prior to colonoscopy or as a split-dose taken on the evening prior to and the morning of colonoscopy. The most commonly studied product for this indication is MoviPrep (Norgine BV).
  • For improving iron absorption: 200 mg of vitamin C per 30 mg of iron.
  • For an age-related eye disease that causes blindness (age-related macular degeneration; AMD: 500 mg of vitamin C, 400 IU of vitamin E, and 15 mg of beta-carotene, with or without 80 mg of zinc, per day for up to 10 years.
  • For treating the common cold: 1-3 grams daily.
  • For slowing progression of hardening of the arteries: 250 mg of slow-release vitamin C in combination with 91 mg (136 IU) of vitamin E twice daily for up to 6 years. Also 500 mg of vitamin C plus 400 IU of vitamin E twice daily for one year has been used.
  • For reducing protein in the urine of patients with type 2 diabetes: 1250 mg of vitamin C with 680 IU of vitamin E per day for 4 weeks has been used.
  • For preventing irregular heart beat after heart surgery: 1-2 grams of vitamin C per day for 1-3 days before heart surgery followed by 1-2 grams in two divided doses daily for 4-5 days after heart surgery has been used.
  • For respiratory infections due to exercise: 600 mg to 1 gram of vitamin C per day for 3-8 weeks before heavy exercise has been used.
  • Worsening of stomach inflammation caused by medicine used to treat H. pylori infection.: 1200 mg of vitamin C daily along with omeprazole has been used.
  • For hemolytic anemia: 200-300 mg of vitamin C three times per week for 3-6 months has been used.
  • For high blood pressure: 500 mg of vitamin C per day along with blood pressure-lowering medication has been used.
  • For preventing nitrate tolerance: 3-6 grams of vitamin C daily has been used.
  • For osteoarthritis: 1 gram of vitamin C in the form of calcium ascorbate daily for 2 weeks has been used.
  • For preventing sunburn: 2 grams of vitamin C along with 1000 IU vitamin E taken before sun exposure has been used.
APPLIED TO THE SKIN:
  • For skin redness/rash: A formulation containing 10% vitamin C, 2% zinc sulfate, and 0.5% tyrosine applied daily for 8 weeks has been used.
  • For wrinkled skin: Most topical preparations used for aged or wrinkled skin are applied daily. Studies have used creams containing 3% to 10% vitamin C. In one study a specific vitamin C formulation (Cellex-C High Potency Serum) used 3 drops applied daily to areas of facial skin. Don't apply vitamin C preparations to the eye or eyelids. Also avoid contact with hair or clothes. It can cause discoloration.
CHILDREN

BY MOUTH:
  • General: The daily recommended dietary allowances (RDAs) are: Infants 0 to 12 months, human milk content (older recommendations specified 30-35 mg); Children 1 to 3 years, 15 mg; Children 4 to 8 years, 25 mg; Children 9 to 13 years, 45 mg; Adolescents 14 to 18 years, 75 mg for boys and 65 mg for girls; Pregnancy and Lactation: age 18 or younger, 115 mg. Do not take more than the following amounts of vitamin C: 400 mg per day for children ages 1 to 3 years, 650 mg per day for children 4 to 8 years, 1200 mg per day for children 9 to 13 years, and 1800 mg per day for adolescents and pregnant and breast-feeding women 14 to 18 years.
  • For tyrosinemia in premature infants on high protein diets: 100 mg of vitamin C.
  • For improving iron absorption: 25-70 mg of vitamin C taken with iron-containing foods has been used.
  • For improving physical performance: 70 mg of vitamin C per day for 2 months has been used in adolescent boys.
BY IV:
  • For tyrosinemia in premature infants on high protein diets: 100 mg of vitamin C has been used.
AS A SHOT:
  • For tyrosinemia in premature infants on high protein diets: 100 mg of vitamin C has been used.

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Pill Finder Tool

Need help identifying pills and medications?
Use the pill identifier tool on RxList.

Therapeutic Research Faculty copyright

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.



Medical Dictionary