Drug & supplement interaction

Vitamin C + Conjugated Estrogens, Meprobamate

Conjugated Estrogens, Meprobamate brand names: PMB 200, PMB 400.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Vitamin C has a moderate interaction with Conjugated Estrogens, Meprobamate. Vitamin C might increase blood levels of estrogens.

Read the full interaction report
SeverityModerate
LikelihoodProbable
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Vitamin C and Conjugated Estrogens, Meprobamate

Here is the interaction we found between these two, with the evidence behind it.

Moderate

ESTROGENS

Why this applies to Conjugated Estrogens, Meprobamate

Conjugated Estrogens, Meprobamate falls under ESTROGENS — the group Vitamin C interacts with.

Vitamin C might increase blood levels of estrogens.
Increases in plasma estrogen levels of up to 55% occur under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy, including topical products. It is suggested that vitamin C prevents oxidation of estrogen in the tissues, regenerates oxidized estrogen, and reduces sulfate conjugation of estrogen in the gut wall. When tissue levels of vitamin C are high, these processes are already maximized and supplemental vitamin C does not have any effect on estrogen levels. Increases in plasma estrogen levels may occur when patients who are deficient in vitamin C take supplements. Monitor these patients for estrogen-related side effects.
Severity Moderate Likelihood Probable Evidence B

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports..

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the short version: high-dose vitamin C may nudge up the estrogen levels from your PMB tablets (the conjugated estrogens part). Vitamin C seems to slow how estrogen gets broken down in the gut wall, so a bit more of it can reach your bloodstream, by as much as 55% in some studies. This isn't about the meprobamate piece, which is a calming agent and works separately.

What might that look like? More of the usual estrogen-related effects, things like breast tenderness, bloating, nausea, headaches, or spotting. The good news is this mostly matters for people who were low in vitamin C to begin with, and food amounts of vitamin C are very unlikely to cause trouble. If you're thinking about a high-dose supplement, just run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. 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.
  2. Morris JC, Beeley L, Ballantine N. Interaction of ethinyloestradiol with ascorbic acid in man [letter]. Br Med J (Clin Res Ed) 1981;283:503.
  3. Vihtamaki T, Parantainen J, Koivisto AM, et al. Oral ascorbic acid increases plasma oestradiol during postmenopausal hormone replacement therapy. Maturitas 2002;42:129-35. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Vitamin C Also Interacts With Other Medications

Vitamin C has 100 moderate, 106 minor known drug interactions in our database — the Conjugated Estrogens, Meprobamate one above is one of them. If you take anything else, check it against the full list below.

Moderate 100 Minor 106 No known interaction 2,624 (incl. Conjugated Estrogens, Meprobamate)
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.

From our Q&A

Questions About Vitamin C or Conjugated Estrogens, Meprobamate

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 Conjugated Estrogens, Meprobamate, 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 Conjugated Estrogens, Meprobamate

This page covers Vitamin C only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Conjugated Estrogens, Meprobamate page lists 187 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 152 moderate · 32 minor.

From our pharmacist’s overview on the Conjugated Estrogens, Meprobamate page

“If you take conjugated estrogens with meprobamate (PMB), a combination that pairs hormone replacement with a sedative, treat this list as a real safety check, not background noise. Three of the 187 entries on file rate major, and they pull in different directions.”

Reviewed by 2 · Jul 18, 2026

Open the Conjugated Estrogens, Meprobamate 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. Your product may carry other ingredients that interact with Conjugated Estrogens, Meprobamate too, on top of Vitamin C — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Vitamin C and Conjugated Estrogens, Meprobamate 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 Conjugated Estrogens, Meprobamate
Steady interest

#2,131 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.

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.

Read the full Vitamin C monograph & all interactions
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
100Moderate
106Minor
2,623No known interaction
100 Moderate 106 Minor 2,623 No interaction
Moderate

100 interactions

Showing 60 of 100 moderate interactions — see all 100 on the Vitamin C page.

Minor

106 interactions

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

No interaction 2,623 drugs checked — show the list

We also checked Vitamin C against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,623 medications checked with no known interaction — see the full Vitamin C list.

See the full Vitamin C interactions page
See every supplement checked against Conjugated Estrogens, Meprobamate, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Vitamin C monograph › Uses, safety, and every drug interaction in one place Conjugated Estrogens, Meprobamate supplement interactions › Every supplement checked against Conjugated Estrogens, Meprobamate, ranked by severity Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Vitamin C and Conjugated Estrogens, Meprobamate Together: Common Questions

Can you take Vitamin C with Conjugated Estrogens, Meprobamate?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Vitamin C and Conjugated Estrogens, Meprobamate interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Conjugated Estrogens, Meprobamate 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.