Drug & supplement interaction

Licorice + 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 Licorice 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. 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

Licorice 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 Licorice 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.

Licorice safety at a glance

Licorice overall Use caution Generally fine in small food amounts, but glycyrrhizin can cause serious problems with high doses or long-term use.
Pregnancy Unsafe When used orally. Licorice has abortifacient, estrogenic, and steroid effects. It can also cause uterine stimulation. Heavy consumption of licorice, equivalent... Read the full pregnancy detail
Breastfeeding Avoid Not enough reliable safety information, so it is best avoided while breastfeeding.

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 Licorice? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Phendimetrazine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Phendimetrazine is filed under a single classification — oral drugs. Licorice has documented interactions with 18 drug classes — the most serious being antihypertensive drugs (moderate), cisplatin (platinol-aq) (moderate) and corticosteroids (moderate) — and none of Phendimetrazine’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

Licorice Does Interact With Other Medications

Licorice has 977 moderate, 63 minor known drug interactions in our database — Phendimetrazine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 977 Minor 63 No known interaction 1,790 (incl. Phendimetrazine)
Taking anything else?

Check Another of Your Medications Against Licorice

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

What to actually watch for

No Interaction Found — But Data Suggests Licorice and Phendimetrazine 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. One of them is worth acting on rather than waiting out — marked below.

  • Raised blood pressure Worth acting on Additional detail

    Licorice

    “Orally, excessive licorice ingestion can lead to pseudohyperaldosteronism, which can precipitate cardiovascular complications such as hypertension and hypertensive crisis, ventricular fibrillation or tachycardia, sinus pause, and cardiac arrest. These effects are due to the licorice constituent glycyrrhizin and usually occur when 20-30 grams or more of licorice product is consumed daily for several weeks.”

    Licorice · Natural Medicines adverse-effect record, reported in arrhythmia.

    6 sources cited
    1. 781. Farese RV Jr, Biglieri EG, Shackleton CH, et al. Licorice-induced hypermineralocorticoidism. N Engl J Med 1991;325:1223-7. PubMed
    2. 15590. Brayley J, Jones J. Life-threatening hypokalemia associated with excessive licorice ingestion (letter). Am J Psychiatry 1994;151:617-8. PubMed
    3. 15592. Dellow EL, Unwin RJ, Honour JW. Pontefract cakes can be bad for you: refractory hypertension and liquorice excess. Nephol Dial Transplant 1999;14:218-20. PubMed
    4. 15594. Eriksson JW, Carlberg B, Hillom V. Life-threatening ventricular tachycardia due to liquorice-induced hypokalemia. J Intern Med 1999;245:307-10.
    5. 15596. Lin SH, Yang SS, Chau T, Halperin ML. An unusual cause of hypokalemic paralysis: chronic licorice ingestion. Am J Med Sci 2003;325:153-6. PubMed
    6. 15597. van den Bosch AE, van der Klooster JM, Zuidgeest DM, et al. Severe hypokalemic paralysis and rhabdomyolysis due to ingestion of liquorice. Neth J Med 2005;63:146-8.

    Phendimetrazine

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

  • A fast or pounding heartbeat Additional detail

    Licorice

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

    Phendimetrazine

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

  • Diarrhea / Nausea Additional detail

    Licorice

    “Nausea and vomiting have been reported rarely following oral use of deglycyrrhizinated licorice.

    Intravenously, the glycyrrhizin constituent of licorice has rarely caused gastric discomfort, diarrhea, or nausea.”

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

    Phendimetrazine

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

  • Headache Additional detail

    Licorice

    “Orally, excessive licorice ingestion can cause a syndrome of apparent mineralocorticoid excess, or pseudohyperaldosteronism, with sodium and water retention, increased urinary potassium loss, hypokalemia, and metabolic alkalosis due to its glycyrrhizin content.”

    Licorice · Natural Medicines adverse-effect record, reported in arrhythmia.

    6 sources cited
    1. 781. Farese RV Jr, Biglieri EG, Shackleton CH, et al. Licorice-induced hypermineralocorticoidism. N Engl J Med 1991;325:1223-7. PubMed
    2. 10619. Hussain RM. The sweet cake that reaches parts other cakes can't! Postgrad Med J 2003;79:115-6.. PubMed
    3. 15591. de Klerk GJ, Nieuwenhuis G, Beutler JJ. Hypokalaemia and hypertension associated with use of liquorice flavoured chewing gum. BMJ 1997;314:731-2.
    4. 15592. Dellow EL, Unwin RJ, Honour JW. Pontefract cakes can be bad for you: refractory hypertension and liquorice excess. Nephol Dial Transplant 1999;14:218-20. PubMed
    5. 15593. Elinav E, Chajek-Shaul T. Licorice consumption causing severe hypokalemic paralysis. Mayo Clin Proc 2003;78:767-8. PubMed
    6. 15594. Eriksson JW, Carlberg B, Hillom V. Life-threatening ventricular tachycardia due to liquorice-induced hypokalemia. J Intern Med 1999;245:307-10.

    Phendimetrazine

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

Reported for Licorice but not commonly for Phendimetrazine: an irregular heartbeat, swelling, kidney problems and muscle weakness.

Effects for Phendimetrazine come from the ADVERSE REACTIONS section of its FDA label; effects for Licorice 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

Licorice in Pregnancy & Breastfeeding

Pregnancy Unsafe

When used orally. Licorice has abortifacient, estrogenic, and steroid effects. It can also cause uterine stimulation. Heavy consumption of licorice, equivalent to 500 mg of glycyrrhizin per week (about 250 grams of licorice per week), during pregnancy seems to increase the risk of delivery before gestational age of 38 weeks. Furthermore, high intake of glycyrrhizin, at least 500 mg per week, during pregnancy is associated with increased salivary cortisol levels in the child by the age of 8 years. This suggests that high intake of licorice during pregnancy may increase hypothalamic-pituitary-adrenocortical axis activity in the child; 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 Phendimetrazine Is Prescribed For, and What Licorice 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. Licorice 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.

Licorice has been studied for:

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

    Licorice for obesity

    It is unclear if oral licorice is beneficial for weight loss.

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 Licorice for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Licorice 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 Licorice 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 Licorice 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

One more smart check

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

We hold 4,721 real supplement products containing Licorice, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Licorice. Even though Licorice itself has no known interaction with Phendimetrazine, 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 Licorice 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 Licorice
Top 5%

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

29 days ago today
Medication Phendimetrazine
Top 25%

#387 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 Licorice reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Licorice 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 Licorice

What is Licorice?

Licorice
  • Sore throat and cough
  • Heartburn and stomach upset
  • Mouth ulcers and digestive complaints
  • Inflammation
  • Traditional tonic/adrenal support

Licorice root is a traditional remedy used for sore throats, coughs, and digestive complaints, but solid human evidence is limited for most uses. Regular licorice contains glycyrrhizin, which can raise blood pressure and lower potassium when taken in large amounts or for a long time, so deglycyrrhizinated (DGL) products are often preferred. Talk to your pharmacist or doctor before using it, especially if you have high blood pressure, heart, or kidney problems.

Glycyrrhiza glabra · Fabaceae · Root · Tea, capsules, tablets (including DGL chewable tablets), liquid extract, lozenges, dried root, candy

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

Licorice: dosing

There is no single well-established standard dose of licorice for any condition, and the safe amount depends on whether the product contains glycyrrhizin. Health authorities generally warn against consuming large amounts of glycyrrhizin, especially daily over weeks or longer.The safest approach is to follow the directions on the product label and not exceed the recommended amount. DGL products are often preferred for ongoing use.

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

Read the full Licorice 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 & Licorice

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

0Major
977Moderate
63Minor
1,789No known interaction
977 Moderate 63 Minor 1,789 No interaction
Moderate

977 interactions

Showing 60 of 977 moderate interactions — see all 977 on the Licorice page.

Minor

63 interactions

Showing 60 of 63 minor interactions — see all 63 on the Licorice page.

No interaction 1,789 drugs checked — show the list

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

Showing the 60 most looked-up of 1,789 medications checked with no known interaction — see the full Licorice list.

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

Licorice References

The 92 references that drive our Licorice 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. Farese RV Jr, Biglieri EG, Shackleton CH, et al. Licorice-induced hypermineralocorticoidism. N Engl J Med 1991;325:1223-7. PubMed
  2. Sigurjonsdottir HA, Ragnarsson J, Franzson L, Sigurdsson G. Is blood pressure commonly raised by moderate consumption of liquorice? J Hum Hypertens 1995;9:345-8.
  3. Armanini D, Lewicka S, Pratesi C, et al. Further studies on the mechanism of the mineralocorticoid action of licorice in humans. J Endocrinol Invest 1996;19:624-9. PubMed
  4. Zhang YD, Lorenzo B, Reidenberg MM. Inhibition of 11 beta hydroxysteroid dehydrogenase obtained from guinea pig kidney by furosemide, naringenin and some other compounds. J Steroid Biochem Mol Biol 1994;49:81-5.
  5. Strandberg TE, Jarvenpaa AL, Vanhanen H, McKeigue PM. Birth outcome in relation to licorice consumption during pregnancy. Am J Epidemiol 2001;153:1085-8. PubMed
  6. Sigurjonsdottir HA, Franzson L, Manhem K, et al. Liquorice-induced rise in blood pressure: a linear dose-response relationship. J Hum Hypertens 2001;15:549-52. PubMed
  7. Amato P, Christophe S, Mellon PL. Estrogenic activity of herbs commonly used as remedies for menopausal symptoms. Menopause 2002;9:145-50. PubMed
  8. Kent UM, Aviram M, Rosenblat M, Hollenberg PF. The licorice root derived isoflavan glabridin inhibits the activities of human cytochrome P450S 3A4, 2B6, and 2C9. Drug Metab Dispos 2002;30:709-15.. PubMed
  9. Yoshida S, Takayama Y. Licorice-induced hypokalemia as a treatable cause of dropped head syndrome. Clin Neurol Neurosurg 2003;105:286-7.. PubMed
  10. Strandberg TE, Andersson S, Jarvenpaa AL, et al. Preterm birth and licorice consumption during pregnancy. Am J Epidemiol 2002;156:803-5.. PubMed
  11. Hussain RM. The sweet cake that reaches parts other cakes can't! Postgrad Med J 2003;79:115-6.. PubMed
  12. Morris DJ, Davis E, Latif SA. Licorice, tobacco chewing, and hypertension. N Engl J Med 1990;322:849-50. PubMed
  13. Quinkler M, Stewart PM. Hypertension and the cortisol-cortisone shuttle. J Clin Endocrinol Metab 2003;88:2384-92. PubMed
  14. Westman EC, Guthrie GP. Licorice, tobacco chewing, and hypertension. N Engl J Med 1990;322:850. PubMed
  15. Mu Y, Zhang J, Zhang S, et al. Traditional Chinese medicines Wu Wei Zi (Schisandra chinensis Baill) and Gan Cao (Glycyrrhiza uralensis Fisch) activate pregnane X receptor and increase warfarin clearance in rats. J Pharmacol Exp Ther 2006;316:1369-77. 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 Licorice and Phendimetrazine Together: Common Questions

Is it safe to take Licorice with Phendimetrazine?
We do not list a known interaction between Licorice 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.
Do Licorice and Phendimetrazine have any of the same side effects?
Yes — our sources link each of them separately to 5 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 Licorice 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 Licorice in each. That is a conversation for your prescriber, especially if Phendimetrazine is being adjusted to a target.
How was the Licorice and Phendimetrazine combination checked?
Interactions in our licensed database are recorded against drug classes. Phendimetrazine is filed under 1 classification, and Licorice has documented interactions with 18 drug classes — none of Phendimetrazine'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 Licorice interact with any other medications?
Yes. Licorice has 1,040 documented drug interactions in our database — Phendimetrazine 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 Phendimetrazine interact with any supplements?
Yes. Phendimetrazine has documented interactions with 17 supplements in our database — Licorice 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

Licorice 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 92 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Phendimetrazine and Licorice?

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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.