Drug & supplement interaction

Periwinkle + Tolazamide

Tolazamide brand name: Tolinase.

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 Periwinkle and Tolazamide 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

Periwinkle and Tolazamide

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 Tolazamide and Periwinkle 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.

Periwinkle safety at a glance

Periwinkle overall Use caution Periwinkle contains strong alkaloids that can be toxic in higher doses, so it should be used carefully and only with professional advice.
Pregnancy Unsafe When used orally; avoid using. Read the full pregnancy detail
Breastfeeding Unsafe When used orally; avoid using. 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 Tolazamide and Periwinkle? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Tolazamide

Interactions in our licensed database are recorded against drug classes, not just single drug names. Tolazamide is filed under 3 classifications — antidiabetes drugs, photosensitizing drugs, oral drugs. Periwinkle has documented interactions with 1 drug class — the most serious being antihypertensive drugs (moderate) — and none of Tolazamide’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

Periwinkle Does Interact With Other Medications

Periwinkle has 172 moderate known drug interactions in our database — Tolazamide isn’t one of them. If you take anything else, check it against the full list below.

Moderate 172 No known interaction 2,658 (incl. Tolazamide)
Taking anything else?

Check Another of Your Medications Against Periwinkle

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

What to actually watch for

What Periwinkle Itself Has Been Linked To

This is not an interaction — nothing below involves Tolazamide. It is the side-effect record for Periwinkle on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Periwinkle, this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

  • Kidney problems Worth acting on Additional detail

    “Periwinkle is generally regarded as unsafe for use. Orally, periwinkle can cause cytotoxic, neurologic, liver, and kidney damage due to its vinca alkaloid constituents (17). Periwinkle has also been reported to cause gastrointestinal complaints, skin flushing, and hypotension (18).”

    Periwinkle · Natural Medicines adverse-effect record, reported in hypotension.

    2 sources cited
    1. 17. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  • Flushing Additional detail

    “Orally, periwinkle can cause skin flushing (18).”

    Periwinkle · Natural Medicines adverse-effect record, reported in niacin-induced flushing.

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  • Low blood pressure Additional detail

    Recorded for Periwinkle in the same Natural Medicines adverse-effect record shown under Kidney problems above.

Everything above comes from the Natural Medicines adverse-effect record for Periwinkle — expand a row for the licensed statement it rests on. We haven’t matched Tolazamide to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Tolazamide.

Special populations

Periwinkle in Pregnancy & Breastfeeding

Pregnancy And Lactation Unsafe

When used orally; 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

Everything else you take

See Every Supplement That Interacts With Tolazamide

This page covers Periwinkle only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tolazamide page lists 272 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Siberian Cocklebur (major), Acai (moderate), African Wild Potato (moderate) and Agaricus Mushroom (moderate).

By severity: 2 major · 230 moderate · 40 minor.

From our pharmacist’s overview on the Tolazamide page

“Tolazamide (Tolinase) lowers blood sugar in type 2 diabetes, and I would handle its supplement list with care, because nearly everything listed can drag blood sugar lower still. Herbs and foods with glucose-lowering effects dominate the file, and stacked on a pill that already lowers glucose they raise the odds of hypoglycemia, blood s…”

Reviewed by 2 · Jul 18, 2026

Open the Tolazamide interaction page

One more smart check

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

We hold 38 real supplement products containing Periwinkle, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Periwinkle. Even though Periwinkle itself has no known interaction with Tolazamide, 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 Periwinkle and Tolazamide 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 Periwinkle
Top half

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

29 days ago today
Medication Tolazamide
Top half

#1,397 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 Periwinkle reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Periwinkle and Tolazamide 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 Periwinkle

What is Periwinkle?

  • Memory and cognitive support
  • Circulation problems
  • Dizziness and ringing in the ears
  • Minor wounds and sore throat (traditional)
  • High blood pressure (traditional)

Periwinkle (Vinca minor) is a flowering plant whose alkaloids are the source of vinpocetine, a compound marketed for memory and brain circulation. Evidence in humans is limited and mixed, and the plant contains potent compounds that can be toxic in larger amounts, so it should be used only with professional guidance. A closely related plant, Madagascar periwinkle, is the source of important cancer chemotherapy drugs but is not safe to use as a home remedy.

Vinca minor · Apocynaceae · Aerial parts (leaves and flowering tops); related compounds come from Catharanthus roseus (Madagascar periwinkle) · Capsules, tablets, dried herb, tinctures, teas, and standardized extracts (such as vinpocetine derived from the plant's alkaloids)

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

Periwinkle: dosing

There is no well-established standard dose for periwinkle as an herb. Products vary widely in strength and in which part of the plant or which extract they contain.If you use a commercial product, follow the directions on the label and do not take more than recommended.

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

Read the full Periwinkle monograph & all interactions
Medication

About Tolazamide

What Is Tolazamide Used For?

Brand name: Tolinase

  • Tolazamide is used along with diet and exercise, and sometimes with other medications, to treat type 2 diabetes (condition in which the body does not use insulin normally and, therefore, cannot control the amount of sugar in the blood). Tolazamide is in a class of medications called sulfonylureas. Tolazamide lowers blood sugar by causing the pancreas to produce insulin (a natural substance that is needed to break down sugar in the body) and helping the body use insulin efficiently. This medication will only help lower blood sugar in people whose bodies produce insulin naturally. Tolazamide is not used to treat type 1 diabetes (condition in which the body does not produce insulin and, therefore, cannot control the amount of sugar in the blood) or diabetic ketoacidosis (a serious condition that may occur if high blood sugar is not treated).

  • Over time, people who have diabetes and high blood sugar can develop serious or life-threatening complications, including heart disease, stroke, kidney problems, nerve damage, and eye problems. Taking medication(s), making lifestyle changes (e.g., diet, exercise, quitting smoking), and regularly checking your blood sugar may help to manage your diabetes and improve your health. This therapy may also decrease your chances of having a heart attack, stroke, or other diabetes-related complications such as kidney failure, nerve damage (numb, cold legs or feet; decreased sexual ability in men and women), eye problems, including changes or loss of vision, or gum disease. Your doctor and other healthcare providers will talk to you about the best way to manage your diabetes.

See full Tolazamide drug information
Keep checking

Other Drugs & Periwinkle

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

0Major
172Moderate
0Minor
2,657No known interaction
172 Moderate 2,657 No interaction
Moderate

172 interactions

Showing 60 of 172 moderate interactions — see all 172 on the Periwinkle page.

No interaction 2,657 drugs checked — show the list

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

Showing the 60 most looked-up of 2,657 medications checked with no known interaction — see the full Periwinkle list.

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

Periwinkle References

The 5 references that drive our Periwinkle 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. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  3. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
  4. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  5. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

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 Periwinkle and Tolazamide Together: Common Questions

Is it safe to take Periwinkle with Tolazamide?
We do not list a known interaction between Periwinkle and Tolazamide. 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.
How was the Periwinkle and Tolazamide combination checked?
Interactions in our licensed database are recorded against drug classes. Tolazamide is filed under 3 classifications, and Periwinkle has documented interactions with 1 drug class — none of Tolazamide'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 Periwinkle interact with any other medications?
Yes. Periwinkle has 172 documented drug interactions in our database — Tolazamide 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 Tolazamide interact with any supplements?
Yes. Tolazamide has documented interactions with 272 supplements in our database — Periwinkle is not one of them. The Tolazamide 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

Periwinkle monograph Uses, safety profile, and every drug interaction in one place Tolazamide drug information The full plain-English guide to this medication Tolazamide supplement interactions Every supplement checked against Tolazamide, 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 5 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Tolazamide and Periwinkle?

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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.