Drug & supplement interaction

Winter Cherry + Efavirenz

Efavirenz brand name: Sustiva.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Winter Cherry and Efavirenz 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

Winter Cherry and Efavirenz

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 Efavirenz and Winter Cherry 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.

Winter Cherry safety at a glance

Winter Cherry overall Use caution Often well tolerated for short-term use, but quality of products and long-term safety are not well established.
Pregnancy Avoid Traditionally avoided in pregnancy because of possible effects on the uterus; do not use.
Breastfeeding Avoid Not enough safety information is available, so it is best avoided while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Efavirenz and Winter Cherry? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Efavirenz

Interactions in our licensed database are recorded against drug classes, not just single drug names. Efavirenz is filed under 8 classifications — including non-nucleoside reverse transcriptase inhibitors (nnrtis), cytochrome p450 2c19 (cyp2c19) inhibitors, cytochrome p450 2c9 (cyp2c9) inhibitors. Winter Cherry has documented interactions with 2 drug classes — the most serious being antidiabetes drugs (moderate) and cytochrome p450 2e1 (cyp2e1) substrates (moderate) — and none of Efavirenz’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

Winter Cherry Does Interact With Other Medications

Winter Cherry has 156 moderate known drug interactions in our database — Efavirenz isn’t one of them. If you take anything else, check it against the full list below.

Moderate 156 No known interaction 2,674 (incl. Efavirenz)
Taking anything else?

Check Another of Your Medications Against Winter Cherry

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

What to actually watch for

What Efavirenz’s Own FDA Label Lists

This is not an interaction — none of it involves Winter Cherry. These are the most notable effects listed in the ADVERSE REACTIONS section of Efavirenz’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. One of them is worth acting on rather than waiting out — marked below.

  • Liver problems Worth acting on
  • Vivid dreams or nightmares
  • Trouble sleeping
  • Tiredness
  • Dizziness
  • A skin rash
  • Vomiting
  • Headache
  • Nausea

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

Everything else you take

See Every Supplement That Interacts With Efavirenz

This page covers Winter Cherry only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Efavirenz page lists 159 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 · 117 moderate · 39 minor.

From our pharmacist’s overview on the Efavirenz page

“Efavirenz (Sustiva) is an HIV medicine, so an interaction that weakens it can cost more than a bad day; it can invite viral resistance. That makes this a list to treat with genuine care.”

Reviewed by 2 · Jul 18, 2026

Open the Efavirenz interaction page

How much people look this up

Where Winter Cherry and Efavirenz 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 Winter Cherry
Steady interest

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

29 days ago today
Medication Efavirenz
Top half

#1,410 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 Winter Cherry reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Winter Cherry and Efavirenz 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 Winter Cherry

What is Winter Cherry?

  • Stress and anxiety
  • Fatigue and low energy
  • Sleep support
  • General vitality and tonic
  • Athletic performance

Winter Cherry is another name for ashwagandha (Withania somnifera), an herb long used in Ayurvedic medicine, most often for stress, sleep, and energy. Some small studies suggest it may help with stress and anxiety, but the evidence is still limited and not definitive. It is generally well tolerated short-term, but pregnant women should avoid it, and anyone with a health condition should check with a pharmacist or doctor first.

Withania somnifera · Solanaceae · Root, and sometimes leaves and berries · Capsules, tablets, powder (churna), root extract, tea, tinctures

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

Winter Cherry: dosing

There is no official standardized dose for Winter Cherry, and products vary widely in strength and how they are made (for example, different root extracts standardized to different amounts of withanolides).Because of this, the best advice is to follow the directions on the product label and not exceed the recommended amount. It is often used for a limited period rather than indefinitely. A pharmacist or doctor can help you choose a reputable product and decide whether it is appropriate for you.

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

Read the full Winter Cherry monograph & all interactions
Medication

About Efavirenz

What Is Efavirenz Used For?

Brand name: Sustiva

Efavirenz is used to treat HIV-1 (human immunodeficiency virus type 1) infection. It is always used together with other antiretroviral medicines — never on its own.

It is approved for adults and for children who are at least 3 months old and weigh at least 3.5 kg (about 7.7 lbs). Both the capsule and tablet forms are approved for this use.

Most-Reported Side Effects for Efavirenz

From FAERS, the FDA’s public side-effect reporting system (0 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Virologic failure 960 reports
Drug resistance 742 reports
Viral mutation identified 676 reports
Pathogen resistance 641 reports
Foetal exposure during pregnancy 621 reports
See full Efavirenz drug information
Keep checking

Other Drugs & Winter Cherry

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

0Major
156Moderate
0Minor
2,673No known interaction
156 Moderate 2,673 No interaction
Moderate

156 interactions

Showing 60 of 156 moderate interactions — see all 156 on the Winter Cherry page.

No interaction 2,673 drugs checked — show the list

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

Showing the 60 most looked-up of 2,673 medications checked with no known interaction — see the full Winter Cherry list.

See the full Winter Cherry interactions page
See every supplement checked against Efavirenz, ranked by severity
Evidence & sources

Winter Cherry References

The 2 references that drive our Winter Cherry 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. Beiraghdar F, Einollahi B, Ghadyani A, et al. A two-week, double-blind, placebo-controlled trial of Viola odorata, Echium amoenum and Physalis alkekengi mixture in symptomatic benign prostate hyperplasia (BPH) men. Pharm Biol 2017;55(1):1800-5.
  2. Hu XF, Zhang Q, Zhang PP, et al. Evaluation of in vitro/in vivo anti-diabetic effects and identification of compounds from Physalis alkekengi. Fitoterapia. 2018;127:129-137. 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 Winter Cherry and Efavirenz Together: Common Questions

Is it safe to take Winter Cherry with Efavirenz?
We do not list a known interaction between Winter Cherry and Efavirenz. 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 Winter Cherry and Efavirenz combination checked?
Interactions in our licensed database are recorded against drug classes. Efavirenz is filed under 8 classifications, and Winter Cherry has documented interactions with 2 drug classes — none of Efavirenz'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 Winter Cherry interact with any other medications?
Yes. Winter Cherry has 156 documented drug interactions in our database — Efavirenz 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 Efavirenz interact with any supplements?
Yes. Efavirenz has documented interactions with 159 supplements in our database — Winter Cherry is not one of them. The Efavirenz 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

Winter Cherry monograph Uses, safety profile, and every drug interaction in one place Efavirenz drug information The full plain-English guide to this medication Efavirenz supplement interactions Every supplement checked against Efavirenz, 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 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Efavirenz and Winter Cherry?

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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.