Drug & supplement interaction

Brewer's Yeast + Atazanavir

Atazanavir brand name: Reyataz.

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 Brewer's Yeast and Atazanavir 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 label for Atazanavir states a food rule worth keeping to, and 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

Brewer's Yeast and Atazanavir

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 Atazanavir and Brewer's Yeast 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.

Brewer's Yeast safety at a glance

Brewer's Yeast overall Use caution Generally well tolerated in food amounts, but it can cause gas and may not be safe for people with weakened immune systems or certain conditions.
Pregnancy Use caution Likely fine in normal food amounts, but the safety of concentrated supplements during pregnancy is not well studied, so check with your provider.
Breastfeeding Use caution Food amounts are likely fine, but there is not enough information on supplement doses, so use caution and ask your provider.

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

Still wondering about combining Atazanavir and Brewer's Yeast? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Atazanavir

Interactions in our licensed database are recorded against drug classes, not just single drug names. Atazanavir is filed under 7 classifications — including protease inhibitors (pis), cytochrome p450 2c9 (cyp2c9) inhibitors, cytochrome p450 1a2 (cyp1a2) inhibitors. Brewer's Yeast has documented interactions with 4 drug classes — the most serious being monoamine oxidase inhibitors (maois) (major), antidiabetes drugs (moderate) and lithium (moderate) — and none of Atazanavir’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

Brewer's Yeast Does Interact With Other Medications

Brewer's Yeast has 9 major, 87 moderate, 40 minor known drug interactions in our database — Atazanavir isn’t one of them. If you take anything else, check it against the full list below.

Major 9 Moderate 87 Minor 40 No known interaction 2,694 (incl. Atazanavir)
Taking anything else?

Check Another of Your Medications Against Brewer's Yeast

Covers the 2,830 medications we’ve checked against Brewer's Yeast. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Brewer's Yeast and Atazanavir 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.

  • Stomach pain Additional detail

    Brewer's Yeast

    “Orally, brewer's yeast can cause intestinal discomfort and flatulence in hypersensitive individuals (2). Anal irritation and abdominal pain have been reported rarely.”

    Brewer's Yeast · Natural Medicines adverse-effect record, reported in flatulence.

    2 sources cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    2. 105170. Gayathri R, Aruna T, Malar S, Shilpa B, Dhanasekar KR. Efficacy of Saccharomyces cerevisiae CNCM I-3856 as an add-on therapy for irritable bowel syndrome. Int J Colorectal Dis. 2020;35(1):139-145. PubMed

    Atazanavir

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

  • Headache Additional detail

    Brewer's Yeast

    “Orally, brewer's yeast can cause migraine-like headaches in sensitive individuals (2).”

    Brewer's Yeast · Natural Medicines adverse-effect record, reported in migraine headache.

    1 source cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.

    Atazanavir

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

Reported for Brewer's Yeast but not commonly for Atazanavir: an allergic reaction, chest pain, a severe allergic reaction and bloating or gas.

Effects for Atazanavir come from the ADVERSE REACTIONS section of its FDA label; effects for Brewer's Yeast come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 14,470 voluntary FDA FAERS reports for Atazanavir that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Atazanavir Products Have a Food Rule — Brewer's Yeast Should Not Break It

At least one FDA label for a product containing Atazanavir says to take it with food. If you take Brewer's Yeast on an empty stomach out of habit, keep them separate — and take Atazanavir with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Atazanavir products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

b For adult patients who cannot swallow the capsules, REYATAZ oral powder is taken once daily with food at the same recommended adult dosage as the capsules along with ritonavir.

From the Dosage and Administration section of the FDA label we read for Atazanavir — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Atazanavir

This page covers Brewer's Yeast only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Atazanavir page lists 152 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 · 107 moderate · 42 minor.

From our pharmacist’s overview on the Atazanavir page

“Atazanavir (Reyataz) treats HIV, and keeping its blood level steady is what stands between viral control and drug resistance, so I read this list with genuine care. Of the 152 supplement and herbal ingredients on file, three carry a major rating: St.”

Reviewed by 2 · Jul 18, 2026

Open the Atazanavir interaction page

One more smart check

Taking Brewer's Yeast as Part of a Dietary Supplement Product? Check It for Interactions

We hold 126 real supplement products containing Brewer's Yeast, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Brewer's Yeast. Even though Brewer's Yeast itself has no known interaction with Atazanavir, 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 Brewer's Yeast and Atazanavir 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 Brewer's Yeast
Top half

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

29 days ago today
Medication Atazanavir
Top half

#725 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 Brewer's Yeast reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Brewer's Yeast and Atazanavir 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 Brewer's Yeast

What is Brewer's Yeast?

Brewer's Yeast
  • Source of B vitamins
  • Diarrhea (certain types)
  • Cold and flu support
  • Digestive health
  • Acne and skin health
  • Blood sugar support

Brewer's yeast is a nutrient-rich fungus that provides B vitamins, protein, and minerals, and a related yeast product (S. boulardii) is used for some types of diarrhea. Most other health claims have limited or weak evidence. It is generally well tolerated as a food or supplement, but talk to your pharmacist or doctor before using it regularly, especially if you have a weakened immune system.

Saccharomyces cerevisiae · Saccharomycetaceae · Whole dried yeast cells (and their fermentation products) · Tablets, capsules, powder, flakes, liquid

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

Brewer's Yeast: dosing

There is no single official or proven dose for brewer's yeast. Products vary widely in their form (tablets, powder, flakes) and in how much yeast they contain.The best approach is to follow the directions on the product label and start with a lower amount to see how your stomach handles it. They can help you decide whether it is appropriate and whether a different, better-studied product (such as a specific probiotic) might be a better fit.

From our Brewer's Yeast monograph — the full record covers uses, side effects and every documented interaction.

Read the full Brewer's Yeast monograph & all interactions
Medication

About Atazanavir

What Is Atazanavir Used For?

Brand name: Reyataz

Atazanavir capsules are used together with other antiretroviral medicines to treat HIV-1 infection in adults and in children 6 years and older who weigh at least 15 kg (about 33 lbs).

Reyataz — available as capsules and as an oral powder — is also approved for HIV-1 treatment in adults and in children as young as 3 months who weigh at least 5 kg (about 11 lbs). Reyataz oral powder must always be taken with ritonavir and food, and is not for use in children weighing less than 5 kg.

Most-Reported Side Effects for Atazanavir

From FAERS, the FDA’s public side-effect reporting system (14,470 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Depression 1,318 reports
Foetal exposure during pregnancy 1,048 reports
Anxiety 878 reports
Emotional distress 660 reports
Anhedonia 601 reports
See full Atazanavir drug information
Keep checking

Other Drugs & Brewer's Yeast

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

9Major
87Moderate
40Minor
2,693No known interaction
9 Major 87 Moderate 40 Minor 2,693 No interaction
Major

9 interactions

Moderate

87 interactions

Showing 60 of 87 moderate interactions — see all 87 on the Brewer's Yeast page.

Minor

40 interactions

No interaction 2,693 drugs checked — show the list

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

Showing the 60 most looked-up of 2,693 medications checked with no known interaction — see the full Brewer's Yeast list.

See the full Brewer's Yeast interactions page
See every supplement checked against Atazanavir, ranked by severity
Evidence & sources

Brewer's Yeast References

The 6 references that drive our Brewer's Yeast 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. Lewis SJ, Freedman AR. Review article: the use of biotherapeutic agents in the prevention and treatment of gastrointestinal disease. Aliment Pharmacol Ther 1998;12:807-22. PubMed
  3. Bahijiri, S. M., Mira, S. A., Mufti, A. M., and Ajabnoor, M. A. The effects of inorganic chromium and brewer's yeast supplementation on glucose tolerance, serum lipids and drug dosage in individuals with type 2 diabetes. Saudi.Med.J. 2000;21(9):831-837. DOI
  4. Schrauzer, G. N. and de, Vroey E. Effects of nutritional lithium supplementation on mood. A placebo-controlled study with former drug users. Biol.Trace Elem.Res. 1994;40(1):89-101. PubMed
  5. Gayathri R, Aruna T, Malar S, Shilpa B, Dhanasekar KR. Efficacy of Saccharomyces cerevisiae CNCM I-3856 as an add-on therapy for irritable bowel syndrome. Int J Colorectal Dis. 2020;35(1):139-145. PubMed
  6. Mourey F, Decherf A, Jeanne JF, et al. Saccharomyces cerevisiae I-3856 in irritable bowel syndrome with predominant constipation. World J Gastroenterol 2022;28(22):2509-2522.

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 Brewer's Yeast and Atazanavir Together: Common Questions

Is it safe to take Brewer's Yeast with Atazanavir?
We do not list a known interaction between Brewer's Yeast and Atazanavir. 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 Brewer's Yeast and Atazanavir have any of the same side effects?
Yes — our sources link each of them separately to 2 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.
Should I take Brewer's Yeast and Atazanavir at the same time of day?
At least one FDA label for a product containing Atazanavir says to take it with food. If you take Brewer's Yeast on an empty stomach out of habit, keep them separate and take Atazanavir with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Atazanavir products can differ — so check the directions on your own box. This is about absorption, not an interaction.
How was the Brewer's Yeast and Atazanavir combination checked?
Interactions in our licensed database are recorded against drug classes. Atazanavir is filed under 7 classifications, and Brewer's Yeast has documented interactions with 4 drug classes — none of Atazanavir'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 Brewer's Yeast interact with any other medications?
Yes. Brewer's Yeast has 136 documented drug interactions in our database — Atazanavir 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 Atazanavir interact with any supplements?
Yes. Atazanavir has documented interactions with 152 supplements in our database — Brewer's Yeast is not one of them. The Atazanavir 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

Brewer's Yeast monograph Uses, safety profile, and every drug interaction in one place Atazanavir drug information The full plain-English guide to this medication Atazanavir supplement interactions Every supplement checked against Atazanavir, 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 6 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Atazanavir and Brewer's Yeast?

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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.