Drug & supplement interaction

Vitamin C + Doxazosin Mesylate

Doxazosin Mesylate brand name: Cardura.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Vitamin C and Doxazosin Mesylate in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Vitamin C and Doxazosin Mesylate

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Doxazosin Mesylate and Vitamin C in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Vitamin C safety at a glance

Vitamin C overall Generally safe Vitamin C is generally safe at normal dietary and supplement doses, but very high doses can cause side effects.
Pregnancy Likely Safe When used orally and appropriately. Read the full pregnancy detail
Breastfeeding Likely Safe When used orally and appropriately. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Doxazosin Mesylate and Vitamin C? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Doxazosin Mesylate

Interactions in our licensed database are recorded against drug classes, not just single drug names. Doxazosin Mesylate is filed under 4 classifications — including alpha-adrenergic antagonists, vasodilators, antihypertensive drugs. Vitamin C has documented interactions with 13 drug classes — the most serious being alkylating agents (moderate), aluminum (moderate) and antitumor antibiotics (moderate) — and none of Doxazosin Mesylate’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Vitamin C Does Interact With Other Medications

Vitamin C has 101 moderate, 106 minor known drug interactions in our database — Doxazosin Mesylate isn’t one of them. If you take anything else, check it against the full list below.

Taking anything else?

Check Another of Your Medications Against Vitamin C

Covers the 2,830 medications we’ve checked against Vitamin C. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Vitamin C and Doxazosin Mesylate May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • Raised blood pressure Worth acting on Additional detail

    Vitamin C

    “Evidence from population research has found that high doses of supplemental vitamin C might not be safe for some people. In postmenopausal adults with diabetes, supplemental vitamin C intake in doses greater than 300 mg per day is associated with increased risk of cardiovascular mortality. However, dietary intake of vitamin C is not associated with this risk.”

    Vitamin C · Natural Medicines adverse-effect record, reported in diabetes.

    5 sources cited
    1. 12498. Lee DH, Folsom AR, Harnack L, et al. Does supplemental vitamin C increase cardiovascular disease risk in women with diabetes? Am J Clin Nutr 2004;80:1194-200. PubMed
    2. 1355. Dwyer JH, Merz NB, Shirocre AM, et al. Progression of early atherosclerosis and intake of vitamin C and vitamin E from supplements and food. The Los Angeles Atherosclerosis Study. 41st Annual Conference on Cardiovascular Disease Epidemiology and Prevent
    3. 83450. Rahimi, R., Nikfar, S., Rezaie, A., and Abdollahi, M. A meta-analysis on the efficacy and safety of combined vitamin C and E supplementation in preeclamptic women. Hypertens.Pregnancy. 2009;28(4):417-434. PubMed
    4. 13162. Ward NC, Hodgson JM, Croft KD, et al. The combination of vitamin C and grape-seed polyphenols increases blood pressure: a randomized, double-blind, placebo-controlled trial. J Hypertens 2005;23:427-34.. PubMed
    5. 114490. Sharma Y, Sumanadasa S, Shahi R, et al. Efficacy and safety of vitamin C supplementation in the treatment of community-acquired pneumonia: a systematic review and meta-analysis with trial sequential analysis. Sci Rep 2024;14(1):11846. PubMed

    Doxazosin Mesylate

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxazosin Mesylate. Read the label on DailyMed ›

  • A higher chance of infection Worth acting on Additional detail

    Vitamin C

    “Hyperoxalosis and oxalate nephropathy have been reported following high-dose infusions of vitamin C. Hyperoxalosis and acute kidney failure contributed to the death of a 76-year-old patient with metastatic adenocarcinoma of the lung who received 10 courses of intravenous infusions containing vitamins, including vitamin C and other supplements over a period of 1 month.”

    Vitamin C · Natural Medicines adverse-effect record, reported in cerebral palsy.

    3 sources cited
    1. 106618. Giffen MA, McLemore JL. Hyperoxalosis Secondary to Intravenous Vitamin C Administration as a Non-Allopathic Treatment for Cancer. Acad Forensic Pathol 2019;9(1-2):118-126. PubMed
    2. 106625. Maike A, Sturgill D, Gallan A. Oxalate Nephropathy in a Renal Transplant Recipient After Receiving High Dose Ascorbic Acid. Am J Med Sci 2021. PubMed
    3. 109962. Shen ZY, Chen YR, Wang MC, Chang SS. High-dose vitamin C-induced acute oxalate nephropathy in a renal transplant recipient: a case report and literature review. Asian J Surg 2022. PubMed

    Doxazosin Mesylate

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxazosin Mesylate. Read the label on DailyMed ›

  • A fast or pounding heartbeat / Low blood pressure Additional detail

    Vitamin C

    Recorded for Vitamin C in the same Natural Medicines adverse-effect record shown under Raised blood pressure above.

    Doxazosin Mesylate

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxazosin Mesylate. Read the label on DailyMed ›

  • Numbness or tingling Additional detail

    Vitamin C

    “Orally, intravenously, and topically, vitamin C is well-tolerated.

    Most Common Adverse Effects:

    Orally: Abdominal cramps, esophagitis, heartburn, headache, osmotic diarrhea, nausea, vomiting. Kidney stones have been reported in those prone to kidney stones.”

    Vitamin C · Natural Medicines adverse-effect record, reported in cluster headache.

    Doxazosin Mesylate

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxazosin Mesylate. Read the label on DailyMed ›

  • Drowsiness / Trouble sleeping / Tiredness Additional detail

    Vitamin C

    “Orally, the adverse effects of vitamin C are dose-related and include fatigue, headache, insomnia, and sleepiness.”

    Vitamin C · Natural Medicines adverse-effect record, reported in cluster headache.

    4 sources cited
    1. 3042. Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed
    2. 4844. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.
    3. 83475. Einerson, B., Nathorn, C., Kitiyakara, C., Sirada, M., and Thamlikitkul, V. The efficacy of ascorbic acid in suboptimal responsive anemic hemodialysis patients receiving erythropoietin: a meta-analysis. J Med.Assoc.Thai. 2011;94 Suppl 1:S134-S146.
    4. 83476. Li, G., Li, L., Yu, C., and Chen, L. Effect of vitamins C and E supplementation on Helicobacter pylori eradication: a meta-analysis. Br.J Nutr 2011;106(11):1632-1637.

    Doxazosin Mesylate

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxazosin Mesylate. Read the label on DailyMed ›

  • Stomach upset Additional detail

    Vitamin C

    “Orally, the adverse effects of vitamin C are dose-related and include nausea, vomiting, esophagitis, heartburn, abdominal cramps, gastrointestinal obstruction, and diarrhea. Doses greater than the tolerable upper intake level (UL) of 2000 mg per day can increase the risk of adverse effects such as osmotic diarrhea and severe gastrointestinal upset.”

    Vitamin C · Natural Medicines adverse-effect record, reported in diarrhea.

    6 sources cited
    1. 3042. Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed
    2. 4844. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.
    3. 96707. Rumbold A, Ota E, Nagata C, Shahrook S, Crowther CA. Vitamin C supplementation in pregnancy. Cochrane Database Syst Rev. 2015;(9):CD004072. PubMed
    4. 104450. Thomas S, Patel D, Bittel B, et al. Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial. JAMA Netw Open. 2 PubMed
    5. 114493. Pejcic AV, Petrovic NZ, Djordjic MD, Milosavljevic MN. Vitamin C Levels in Pregnant Women and the Efficacy of Vitamin C Supplements in Preventing Premature Rupture of Membranes: A Systematic Review and Meta-Analysis. Balkan Med J 2024;41(4):248-260. PubMed
    6. 114490. Sharma Y, Sumanadasa S, Shahi R, et al. Efficacy and safety of vitamin C supplementation in the treatment of community-acquired pneumonia: a systematic review and meta-analysis with trial sequential analysis. Sci Rep 2024;14(1):11846. PubMed

    Doxazosin Mesylate

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxazosin Mesylate. Read the label on DailyMed ›

  • Stomach pain Additional detail

    Vitamin C

    Recorded for Vitamin C in the same Natural Medicines adverse-effect record shown under Numbness or tingling above.

    Doxazosin Mesylate

    Listed in the ADVERSE REACTIONS section of the FDA label for Doxazosin Mesylate. Read the label on DailyMed ›

Showing the 10 most notable of 14 shared effects — ranked by how unusual each one is, not just whether both lists mention it.

Reported for Vitamin C but not commonly for Doxazosin Mesylate: kidney problems, increased thirst, kidney stones and heartburn.

Effects for Doxazosin Mesylate come from the ADVERSE REACTIONS section of its FDA label; effects for Vitamin C come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Vitamin C in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Safe

When used orally and appropriately.

Pregnancy And Lactation Possibly Unsafe

When used orally in excessive doses. Tell patients over age 19 not to use doses exceeding the UL of 2000 mg daily when pregnant or breast-feeding and for those 14-18 years of age not to use doses exceeding 1800 mg daily when pregnant or breast-feeding. Higher doses can cause osmotic diarrhea and gastrointestinal upset. Large doses of vitamin C during pregnancy can also cause newborn scurvy; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Overlapping uses

What Doxazosin Mesylate Is Prescribed For, and What Vitamin C Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Doxazosin Mesylate is a prescription medicine with approved uses on its FDA label. Vitamin C is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Doxazosin Mesylate is prescribed for: Doxazosin tablets — sold as Cardura, Doxazosin, and Doxazosin mesylate — treat two conditions: the urinary symptoms of benign prostatic hyperplasia (BPH, an enlarged prostate) and high blood pressure (hypertension). For hypertension, lowering blood pressure reduces the risk of serious events like stroke and heart attack. Cardura XL (extended-release tablet) is approved only for BPH symptoms. It is not approved for the treatment of hypertension.

Vitamin C has been studied for:

  • Hypertension Natural Medicines rates the evidence for Vitamin C: Possibly Effective Read what the research shows

    Vitamin C for hypertension

    Oral vitamin C seems to modestly reduce blood pressure in patients with hypertension, but some evidence is conflicting.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Doxazosin Mesylate on your own; if you are taking Vitamin C for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Vitamin C or Doxazosin Mesylate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Vitamin C or Doxazosin Mesylate, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Doxazosin Mesylate

This page covers Vitamin C only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Doxazosin Mesylate page lists 137 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Tyramine (major) and Adrafinil (moderate).

By severity: 4 major · 112 moderate · 21 minor.

From our pharmacist’s overview on the Doxazosin Mesylate page

“Doxazosin (Cardura) relaxes blood vessels to lower blood pressure and ease enlarged-prostate symptoms, and it already has a reputation for dizziness and first-dose fainting. That is why its list of 137 interacting supplements deserves genuine respect.”

Reviewed by 2 · Jul 18, 2026

Open the Doxazosin Mesylate interaction page

One more smart check

Taking Vitamin C as Part of a Dietary Supplement Product? Check It for Interactions

We hold 36,382 real supplement products containing Vitamin C, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Vitamin C. Even though Vitamin C itself has no known interaction with Doxazosin Mesylate, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Vitamin C and Doxazosin Mesylate Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Vitamin C
Most looked up

#1 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Doxazosin Mesylate
Top half

#883 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Vitamin C reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Vitamin C and Doxazosin Mesylate records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Vitamin C

What is Vitamin C?

  • Common cold and immune support
  • Antioxidant support
  • Skin health and collagen formation
  • Wound healing
  • Preventing or treating scurvy
  • Improving iron absorption

Vitamin C (ascorbic acid) is an essential nutrient your body needs but cannot make, so you must get it from food or supplements. It's important for immune function, collagen, and acts as an antioxidant, but taking large doses doesn't prevent colds for most people and may cause stomach upset. Most people get enough from a balanced diet, so check with your pharmacist or doctor before taking high-dose supplements.

Not applicable (a water-soluble vitamin; found in fruits and vegetables) · Tablets, capsules, chewables, gummies, effervescent powders, liquids, and intravenous (in medical settings)

An interaction check asks whether these two react with each other — it does not ask whether Vitamin C is a good idea for someone in your situation. Here is what our Vitamin C record says about it on its own.

Vitamin C: dosing

For everyday nutrition, vitamin C needs are met through a balanced diet and standard multivitamins, and recommended daily amounts vary by age, sex, and life stage. Smokers generally need somewhat more.There is no single agreed-upon "treatment" dose for the supplement uses people are interested in. Because high doses can cause stomach upset and other problems, more is not always better.

From our Vitamin C monograph — the full record covers uses, side effects and every documented interaction.

Read the full Vitamin C monograph & all interactions
Medication

About Doxazosin

What Is Doxazosin Used For?

Brand name: Cardura

Doxazosin tablets — sold as Cardura, Doxazosin, and Doxazosin mesylate — treat two conditions: the urinary symptoms of benign prostatic hyperplasia (BPH, an enlarged prostate) and high blood pressure (hypertension). For hypertension, lowering blood pressure reduces the risk of serious events like stroke and heart attack.

Cardura XL (extended-release tablet) is approved only for BPH symptoms. It is not approved for the treatment of hypertension.

See full Doxazosin drug information
Keep checking

Other Drugs & Vitamin C

Browse every other medication we’ve checked against Vitamin C — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
101Moderate
106Minor
2,622No known interaction
Moderate

101 interactions

Showing 60 of 101 moderate interactions — see all 101 on the Vitamin C page.

Minor

106 interactions

Showing 60 of 106 minor interactions — see all 106 on the Vitamin C page.

No interaction 2,622 drugs checked — show the list
Evidence & sources

Vitamin C References

The 51 references that drive our Vitamin C monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Back DJ, Breckenridge AM, MacIver M, et al. Interaction of ethinyloestradiol with ascorbic acid in man. Br Med J (Clin Res Ed) 1981;282:1516.
  3. Morris JC, Beeley L, Ballantine N. Interaction of ethinyloestradiol with ascorbic acid in man [letter]. Br Med J (Clin Res Ed) 1981;283:503.
  4. Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
  5. Dwyer JH, Merz NB, Shirocre AM, et al. Progression of early atherosclerosis and intake of vitamin C and vitamin E from supplements and food. The Los Angeles Atherosclerosis Study. 41st Annual Conference on Cardiovascular Disease Epidemiology and Prevent
  6. Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed
  7. Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
  8. Segal S, Kaminski S. Drug-nutrient interactions. American Druggist 1996 Jul;42-8.
  9. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.
  10. Houston JB, Levy G. Drug biotransformation interactions in man VI: Acetaminophen and ascorbic acid. J Pharm Sci 1976;65:1218-21. PubMed
  11. Brown BG, Zhao XQ, Chait A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med 2001;345:1583-93. DOI
  12. Rosenthal G. Interaction of ascorbic acid and warfarin. JAMA 1971;215:1671. DOI
  13. Hume R, Johnstone JM, Weyers E. Interaction of ascorbic acid and warfarin. JAMA 1972;219:1479. DOI
  14. Smith EC, Skalski RJ, Johnson GC, Rossi GV. Interaction of ascorbic acid and warfarin. JAMA 1972;221:1166. DOI
  15. Traxer O, Huet B, Poindexter J, et al. Effect of ascorbic acid consumption on urinary stone risk factors. J Urol 2003;170:397-401.. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Vitamin C and Doxazosin Mesylate Together: Common Questions

Is it safe to take Vitamin C with Doxazosin Mesylate?
We do not list a known interaction between Vitamin C and Doxazosin Mesylate. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Vitamin C and Doxazosin Mesylate have any of the same side effects?
Yes — our sources link each of them separately to 10 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Are Vitamin C and Doxazosin Mesylate used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Vitamin C in each. That is a conversation for your prescriber, especially if Doxazosin Mesylate is being adjusted to a target.
How was the Vitamin C and Doxazosin Mesylate combination checked?
Interactions in our licensed database are recorded against drug classes. Doxazosin Mesylate is filed under 4 classifications, and Vitamin C has documented interactions with 13 drug classes — none of Doxazosin Mesylate's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Vitamin C interact with any other medications?
Yes. Vitamin C has 207 documented drug interactions in our database — Doxazosin Mesylate is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Doxazosin Mesylate interact with any supplements?
Yes. Doxazosin Mesylate has documented interactions with 137 supplements in our database — Vitamin C is not one of them. The Doxazosin Mesylate interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Doxazosin Mesylate and Vitamin C?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.