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5 Interactions found for:

allopurinol and Vitamin C
Interactions Summary
  • 2 Major
  • 1 Moderate
  • 2 Minor
  • allopurinol
  • Vitamin C

Drug Interactions

No drug interactions were found for selected drugs: allopurinol, Vitamin C.

This does not necessarily mean no interactions exist. Always consult your healthcare provider.

Drug and Food Interactions

Moderate
Allopurinol + Food

The following applies to the ingredients: Allopurinol

Allopurinol should generally be taken after a meal to reduce side effects. If your daily dose exceeds 300 mg, you may also ask your healthcare provider if it is okay to divide the total daily dose into smaller doses given more frequently instead of once a day, as this may also reduce stomach upset that can happen with allopurinol. It is best to avoid or limit the consumption of alcohol, as it can increase drowsiness or other nervous system side effects of allopurinol. You should also avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Drug and Pregnancy Interactions

The following applies to the ingredients: Allopurinol

Professional Content

Safety has not been established.
-According to some authorities: This drug is only recommended for use during pregnancy when there are no safer alternatives and the benefit outweighs the risk.

AU TGA pregnancy category: B2
US FDA pregnancy category: Not assigned

Risk Summary: Based on findings in animals, this drug may cause fetal harm.

Comments:
-Animals exposed to this drug have shown negative developmental effects.
-Placental transfer of this drug and its metabolite have been reported.
-The available data on the use of this drug during pregnancy is limited and inconclusive. Pregnant women should be apprised of the potential risk to the fetus.
-This drug has been used widely for many years without apparent harmful effects.
-Infertility and impotence in men rarely occur during treatment with this drug, and studies have not confirmed an association with it.

Animal studies have failed to reveal evidence of fetotoxicity or teratogenicity. However, intraperitoneal administration of this drug in pregnant mice on gestation days 10 or 13 produced significant increases in fetal deaths and teratogenic effects (cleft palate, harelip, and digital defects). In another study, this drug after oral administration to pregnant rats during organogenesis caused embryonic resorptions, growth retardation, decreased fetal weight, and skeletal, liver, kidney, and brain abnormalities. A 2013 report analyzed 31 pregnancies exposed to this drug during the first trimester, finding that major birth defects and miscarriages were within the general population's range, but one child had severe defects. There is insufficient data in human pregnancy.

AU TGA pregnancy category B2: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals are inadequate or may be lacking, but available data show no evidence of an increased occurrence of fetal damage.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

References

  1. "Product Information. Allosig (allopurinol)." Arrow Pharma Pty Ltd 18 March 2025 (2025):
  2. "Product Information. Zyloric (allopurinol)." Aspen Pharma Trading Ltd 19 Feb 2025 (2025):
  3. "Product Information. Aloprim (allopurinol)." Mylan Institutional LLC 2/2022 (2022):
  4. "Product Information. Zyloprim (allopurinol)." Casper Pharma LLC 9/2023 (2023):
  5. "Product Information. Allopurinol (allopurinol)." Leading Pharma, LLC 9/2024 (2024):

The following applies to the ingredients: Ascorbic Acid (found in Vitamin C)

Professional Content

Ascorbic acid has been assigned to pregnancy category A by the FDA when used in doses that are advocated by the FDA. Doses exceeding the recommended dietary allowance (RDA) have been assigned to pregnancy category C. Animal studies have not been reported. There are no controlled data in human pregnancy. Ascorbic acid is only recommended for use during pregnancy when benefit outweighs risk.

High doses of ascorbic acid taken during pregnancy have been reported to cause conditional scurvy in infants following birth.

References

  1. "Product Information. Cemill 500 (ascorbic acid)." Abbott Pharmaceutical PROD
  2. Briggs GG, Freeman RK, Yaffe SJ.. "Drugs in Pregnancy and Lactation." Philadelphia, PA: Lippincott Williams & Wilkins (2002):

Drug and Breastfeeding Interactions

The following applies to the ingredients: Allopurinol

Professional Content

Breastfeeding is not recommended during use of this drug and for 1 week after the last dose.

Excreted into human milk: Yes

Comments:
-This drug and its active metabolite were detected in human milk.
-There was no report of effects of this drug on the nursing infant or on milk production.
-If the mother requires this drug, she does not have to stop nursing, but the nursing infant should be monitored for allergic reactions (such as rash) and undergo periodic CBC and differential blood counts.

References

  1. Bethesda (MD): National Institute of Child Health and Human Development (US) "Allopurinol - Drugs and Lactation Database (LactMed) https://www.ncbi.nlm.nih.gov/books/NBK501198/" (2025):
  2. "Product Information. Allosig (allopurinol)." Arrow Pharma Pty Ltd 18 March 2025 (2025):
  3. "Product Information. Zyloric (allopurinol)." Aspen Pharma Trading Ltd 19 Feb 2025 (2025):
  4. "Product Information. Aloprim (allopurinol)." Mylan Institutional LLC 2/2022 (2022):
  5. "Product Information. Zyloprim (allopurinol)." Casper Pharma LLC 9/2023 (2023):
  6. "Product Information. Allopurinol (allopurinol)." Leading Pharma, LLC 9/2024 (2024):

The following applies to the ingredients: Ascorbic Acid (found in Vitamin C)

Professional Content

Ascorbic acid is excreted into human breast milk. The effects in the nursing infant are unknown. The manufacturer recommends that caution be used when administering ascorbic acid to nursing women.

References

  1. "Product Information. Cemill 500 (ascorbic acid)." Abbott Pharmaceutical PROD

Therapeutic Duplication Warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

Switch to: Professional Interactions

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.

Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

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