Drug & supplement interaction

Prenatal Vitamins + Phendimetrazine

Phendimetrazine brand names: Plegine, Metra, Weightrol.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Prenatal Vitamins and Phendimetrazine 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.

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Interaction report

Prenatal Vitamins and Phendimetrazine

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 Phendimetrazine and Prenatal Vitamins 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Prenatal Vitamins at all — not against Phendimetrazine, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Prenatal Vitamins safety at a glance

Prenatal Vitamins overall Generally safe Generally safe when taken as directed, though they can cause mild stomach upset or constipation.
Pregnancy Likely Safe When used orally. Prenatal vitamins contain many different minerals, vitamins, and sometimes other dietary supplement ingredients. Each individual ingredient ha... Read the full pregnancy detail
Breastfeeding Possibly Safe When used orally. Prenatal vitamins usually do not contain ingredients in amounts that exceed the tolerable upper intake level (UL). The UL is the highest level... 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 Phendimetrazine and Prenatal Vitamins? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Phendimetrazine’s Own FDA Label Lists

This is not an interaction — none of it involves Prenatal Vitamins. These are the most notable effects listed in the ADVERSE REACTIONS section of Phendimetrazine’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 2 of them are worth acting on rather than waiting out — marked below.

  • Pain or burning when passing urine Worth acting on
  • Raised blood pressure Worth acting on
  • Tremor or shakiness
  • Flushing
  • Sweating
  • A fast or pounding heartbeat
  • Anxiety or restlessness
  • Trouble sleeping
  • Constipation
  • Stomach pain

Showing the 10 most notable of 14 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Phendimetrazine. Read the label on DailyMed › Prenatal Vitamins’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Prenatal Vitamins side to compare — that is a limit of the record, not a statement that Prenatal Vitamins has no side effects.

Special populations

Prenatal Vitamins in Pregnancy & Breastfeeding

Pregnancy Likely Safe

When used orally. Prenatal vitamins contain many different minerals, vitamins, and sometimes other dietary supplement ingredients. Each individual ingredient has a unique safety profile. Clinical studies evaluating prenatal vitamins show that prenatal vitamins are safe when used appropriately during pregnancy.

Lactation Possibly Safe

When used orally. Prenatal vitamins usually do not contain ingredients in amounts that exceed the tolerable upper intake level (UL). The UL is the highest level of nutrient intake that is unlikely to have a risk of adverse effects for most people, as determined by the Food and Nutrition Board and the National Academies of Science. Therefore, prenatal vitamins have apparent safety during lactation. However, high quality research assessing the safety of prenatal vitamins during lactation is lacking.

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 Phendimetrazine Is Prescribed For, and What Prenatal Vitamins Has Been Studied For

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

Phendimetrazine is prescribed for: Phendimetrazine tartrate is used to help manage exogenous obesity (excess body weight from outside causes like diet and lifestyle) as a short-term addition to a calorie-restricted diet. It is intended for adults with a BMI of 30 or higher, or a BMI of 27 or higher when other risk factors — such as high blood pressure, diabetes, or high cholesterol — are also present. It is approved for use as monotherapy only, meaning it must not be combined with other weight-loss drugs or stimulants. Both the tablet form and the extended-release capsule form are approved for this purpose.

Read the rest of what Phendimetrazine is prescribed for

This medication is meant to be used for only a few weeks as part of a broader weight-management plan.

Prenatal Vitamins has been studied for:

  • Obesity studied, not established Prenatal Vitamins has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Prenatal Vitamins for obesity

    Retrospective research suggests that maternal intake of prenatal vitamins during pregnancy has very little effect on the risk of childhood obesity. In a large retrospective study of children aged 3 to 6.5 years who had been born small for gestational age, prenatal use of a multivitamin product alone, as reported by the mother, did not influence the risk of obesity, but did add to the benefit of prenatal folic acid in…

    2 sources cited
    1. 94598. Dougan MM, Willett WC, Michels KB. Prenatal vitamin intake during pregnancy and offspring obesity. Int J Obes. 2015;39(1):69-74. PubMed
    2. 112766. Lu Q, Strodl E, Liang Y, Huang LH, Hu BJ, Chen WQ. Joint Effects of Prenatal Folic Acid Supplement with Prenatal Multivitamin and Iron Supplement on Obesity in Preschoolers Born SGA: Sex Specific Difference. Nutrients 2023;15(2):380. PubMed

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 Phendimetrazine on your own; if you are taking Prenatal Vitamins for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Prenatal Vitamins or Phendimetrazine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Prenatal Vitamins or Phendimetrazine, 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 Phendimetrazine

This page covers Prenatal Vitamins only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phendimetrazine page lists 17 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 9 minor.

From our pharmacist’s overview on the Phendimetrazine page

“Of the 17 supplements on file for phendimetrazine, an appetite-suppressant stimulant prescribed short term for weight loss, activated charcoal is the one that demands real caution. Charcoal binds medications in the gut and can sharply cut how much of a drug your body absorbs, leaving you with less appetite control than your prescriptio…”

Reviewed by 2 · Jul 18, 2026

Open the Phendimetrazine interaction page

How much people look this up

Where Prenatal Vitamins and Phendimetrazine 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 Prenatal Vitamins
Steady interest

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

29 days ago today
Medication Phendimetrazine
Top 10%

#198 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 Prenatal Vitamins reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Prenatal Vitamins and Phendimetrazine records this page draws on were last updated July 11, 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 Prenatal Vitamins

What is Prenatal Vitamins?

  • Nutritional support before and during pregnancy
  • Preventing neural tube defects (folic acid)
  • Supporting healthy fetal development
  • Preventing iron-deficiency anemia in pregnancy
  • Support during breastfeeding

Prenatal vitamins are multivitamin-mineral supplements designed to fill nutritional gaps before and during pregnancy and while breastfeeding, with folic acid and iron being especially important. They are widely recommended by doctors, but they do not replace a healthy diet, and you should choose a product and dose with guidance from your pharmacist or doctor.

Tablets, capsules, soft gels, chewables, gummies, liquids

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

Prenatal Vitamins: dosing

There is no single "correct" prenatal vitamin, since products differ in their ingredients and amounts. Most are taken once daily, but some require more than one tablet or a separate DHA softgel.

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

Read the full Prenatal Vitamins monograph & all interactions
Medication

About Phendimetrazine

What Is Phendimetrazine Used For?

Brand names: Plegine, Metra, Weightrol

Phendimetrazine tartrate is used to help manage exogenous obesity (excess body weight from outside causes like diet and lifestyle) as a short-term addition to a calorie-restricted diet. It is intended for adults with a BMI of 30 or higher, or a BMI of 27 or higher when other risk factors — such as high blood pressure, diabetes, or high cholesterol — are also present.

It is approved for use as monotherapy only, meaning it must not be combined with other weight-loss drugs or stimulants. Both the tablet form and the extended-release capsule form are approved for this purpose. This medication is meant to be used for only a few weeks as part of a broader weight-management plan.

See full Phendimetrazine drug information
Keep checking

Other Drugs & Prenatal Vitamins

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Prenatal Vitamins list.

See the full Prenatal Vitamins interactions page
See every supplement checked against Phendimetrazine, ranked by severity
Evidence & sources

Prenatal Vitamins References

The 18 references that drive our Prenatal Vitamins 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. Dietary reference intakes (DRIs): estimated average requirements. Food and Nutrition Board, Institute of Medicine, National Academics. https://www.nal.usda.gov/sites/default/files/fnic_uploads//recommended_intakes_individuals.pdf Accessed July 24, 2017.
  2. Bentley S, Hermes A, Phillips D, Daoud YA, Hanna S. Comparative effectiveness of a prenatal medical food to prenatal vitamins on hemoglobin levels and adverse outcomes: a retrospective analysis. Clin Ther. 2011;33(2):204-10. PubMed
  3. Braun JM, Froehlich T, Kalkbrenner A. Brief report: are autistic-behaviors in children related to prenatal vitamin use and maternal whole blood folate concentrations? J Autism Dev Disord. 2014;44(10):2602-7. PubMed
  4. Dougan MM, Willett WC, Michels KB. Prenatal vitamin intake during pregnancy and offspring obesity. Int J Obes. 2015;39(1):69-74. PubMed
  5. Sauder KA, Starling AP, Shapiro AL, et al. Exploring the association between maternal prenatal multivitamin use and early infant growth: The Healthy Start Study. Pediatr Obes. 2016;11(5):434-41. PubMed
  6. Riley LE, Stark AR, Kilpatrick SJ, et al. Guidelines for Perinatal Care. 7th ed. Washington, DC: The American Academy of Pediatrics and the American College of Obstetricians and Gynecologists; 2012.
  7. Czeizel AE, Dudás I. Prevention of the first occurrence of neural-tube defects by periconceptional vitamin supplementation. N Engl J Med. 1992;327(26):1832-5. PubMed
  8. Czeizel AE. Prevention of congenital abnormalities by periconceptional multivitamin supplementation. BMJ. 1993;306(6893):1645-8. PubMed
  9. Scholl TO, Hediger ML, Bendich A, et al. Use of multivitamin/mineral prenatal supplements: influence on the outcome of pregnancy. Am J Epidemiol. 1997;146(2):134-41. PubMed
  10. Goh YI, Bollano E, Einarson TR, Koren G. Prenatal multivitamin supplementation and rates of pediatric cancers: a meta-analysis. Clin Pharmacol Ther. 2007 May;81(5):685-91. PubMed
  11. Goh YI, Bollano E, Einarson TR, Koren G. Prenatal multivitamin supplementation and rates of congenital anomalies: a meta-analysis. J Obstet Gynaecol Can. 2006 Aug;28(8):680-9. Review. PubMed
  12. Balogun OO, da Silva Lopes K, Ota E, et al. Vitamin supplementation for preventing miscarriage. Cochrane Database Syst Rev. 2016 May 6;(5):CD004073. PubMed
  13. Dean SV, Lassi ZS, Imam AM, Bhutta ZA. Preconception care: nutritional risks and interventions. Reprod Health. 2014;11 Suppl 3:S3. PubMed
  14. Virk J, Liew Z, Olsen J, Nohr EA, Catov JM, Ritz B. Pre-conceptual and prenatal supplementary folic acid and multivitamin intake, behavioral problems, and hyperkinetic disorders: A study based on the Danish National Birth Cohort (DNBC). Nutr Neurosci. 201 PubMed
  15. Wolf HT, Hegaard HK, Huusom LD, Pinborg AB. Multivitamin use and adverse birth outcomes in high-income countries: a systematic review and meta-analysis. Am J Obstet Gynecol. 2017;217(4):404.e1-404.e30. 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 Prenatal Vitamins and Phendimetrazine Together: Common Questions

Is it safe to take Prenatal Vitamins with Phendimetrazine?
We do not list a known interaction between Prenatal Vitamins and Phendimetrazine. 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.
Are Prenatal Vitamins and Phendimetrazine 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 Prenatal Vitamins in each. That is a conversation for your prescriber, especially if Phendimetrazine is being adjusted to a target.
Does Phendimetrazine interact with any supplements?
Yes. Phendimetrazine has documented interactions with 17 supplements in our database — Prenatal Vitamins is not one of them. The Phendimetrazine interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Prenatal Vitamins monograph Uses, safety profile, and every drug interaction in one place Phendimetrazine drug information The full plain-English guide to this medication Phendimetrazine supplement interactions Every supplement checked against Phendimetrazine, 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 References The 18 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Phendimetrazine and Prenatal Vitamins?

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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.