Drug & supplement interaction

Casein Peptides + Hydroxyzine

Hydroxyzine brand names: Atarax, Vistaril, Ucerax.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated June 2026 · Pair last verified Sep 20, 2026

The bottom line No known interaction

We found no known interaction between Casein Peptides and Hydroxyzine 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

Casein Peptides and Hydroxyzine

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 Hydroxyzine and Casein Peptides 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.

Casein Peptides safety at a glance

Casein Peptides overall Use caution Generally well tolerated in healthy adults, but people with milk allergy should avoid them.

Pregnancy Use caution Not enough reliable safety data, so it is best to avoid concentrated supplements unless advised by your doctor.

Breastfeeding Use caution Safety of supplement doses is not well studied, so caution is advised.

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

Still wondering about combining Hydroxyzine and Casein Peptides? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Hydroxyzine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Hydroxyzine is filed under 5 classifications — including anticholinergic drugs, photosensitizing drugs, seizure threshold lowering drugs. Casein Peptides has documented interactions with 1 drug class — the most serious being antihypertensive drugs (moderate) — and none of Hydroxyzine’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

Casein Peptides Does Interact With Other Medications

Casein Peptides has 172 moderate known drug interactions in our database — Hydroxyzine 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. Hydroxyzine)

Taking anything else?

Check Another of Your Medications Against Casein Peptides

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

What to actually watch for

What Hydroxyzine’s Own FDA Label Lists

This is not an interaction — none of it involves Casein Peptides. These are the most notable effects listed in the ADVERSE REACTIONS section of Hydroxyzine’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. 5 of them are worth acting on rather than waiting out — marked below.

Hallucinations Worth acting on
An irregular heartbeat Worth acting on
Seizures Worth acting on
Hives Worth acting on
An allergic reaction Worth acting on
Tremor or shakiness
Dry mouth
Drowsiness
Itching mentioned in 6.7% of FDA reports for Hydroxyzine
Headache mentioned in 4.8% of FDA reports for Hydroxyzine

Showing the 10 most notable of 11 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 Hydroxyzine. Read the label on DailyMed › Where a percentage is shown, it is the share of 50,845 voluntary FDA FAERS reports for Hydroxyzine that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Casein Peptides’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Casein Peptides side to compare — that is a limit of the record, not a statement that Casein Peptides has no side effects.

Overlapping uses

What Hydroxyzine Is Prescribed For, and What Casein Peptides Has Been Studied For

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

Hydroxyzine is prescribed for: Hydroxyzine is used to relieve anxiety and tension related to psychoneurosis (anxiety-based mental health conditions) and as a supportive treatment when anxiety is part of another medical condition. Oral forms — including tablets, capsules, and oral solution — are used for anxiety relief and to manage itching (pruritus) caused by allergic conditions such as chronic urticaria (hives), atopic dermatitis, contact dermatitis, and histamine-driven itch. Oral forms are also used as a sedative before and after surgery or general anesthesia. Hydroxyzine Hydrochloride intramuscular injection is used specifically when a shot is needed — for example, in acute psychiatric or emotional emergencies, acute alcohol withdrawal with anxiety symptoms or delirium tremens, control of nausea and vomiting (except during pregnancy), and as pre- and post-operative or pre- and post-partum supportive medication to reduce narcotic requirements and control nausea.

Casein Peptides has been studied for:

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

Casein Peptides for anxiety

Although there has been interest in using oral casein peptides for anxiety, there is insufficient reliable information about the clinical effects of casein peptides for this purpose.

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

From our Q&A

Questions About Casein Peptides or Hydroxyzine

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

This page covers Casein Peptides only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Hydroxyzine page lists 183 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Henbane (major), Scopolia (major) and St. John's Wort (major).

By severity: 5 major · 135 moderate · 43 minor.

From our pharmacist’s overview on the Hydroxyzine page

“Hydroxyzine (Atarax, Vistaril) is a sedating antihistamine for itching and anxiety, so read this list closely before pairing it with any supplement. Five of the 183 ingredients on file rate major, and those come first: grapefruit and St.”

Reviewed by 2 · Jul 18, 2026

Open the Hydroxyzine interaction page

One more smart check

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

We hold 82 real supplement products containing Casein Peptides, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Casein Peptides. Even though Casein Peptides itself has no known interaction with Hydroxyzine, 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 Casein Peptides and Hydroxyzine 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 Casein Peptides

Steady interest

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

29 days ago today

Medication Hydroxyzine

Top 25%

#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 Casein Peptides reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Casein Peptides and Hydroxyzine records this page draws on were last updated June 22, 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 Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Casein Peptides

What is Casein Peptides?

High blood pressure
Stress and relaxation
Sleep support
General wellness/protein supplement

Casein peptides are small protein fragments made from milk casein, often studied for mild blood pressure support and relaxation. The evidence is limited and mostly modest, so they should not replace proven treatments. People with milk allergy should avoid them, and anyone with a health condition should check with a pharmacist or doctor first.

Casein protein from milk (cow's milk) · Capsules, tablets, powders, functional foods and drinks

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

Casein Peptides: dosing

There is no official or standardized dose of casein peptides. The amounts used in studies have varied widely depending on the specific peptide and product, and there is no single agreed-upon effective dose.If you choose to use a casein peptide product, follow the directions on the label and do not exceed the recommended amount. They can help you decide whether the product is appropriate and which form makes sense for you.

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

Read the full Casein Peptides monograph & all interactions

Medication

About Hydroxyzine

What Is Hydroxyzine Used For?

Brand names: Atarax, Vistaril, Ucerax

Hydroxyzine is used to relieve anxiety and tension related to psychoneurosis (anxiety-based mental health conditions) and as a supportive treatment when anxiety is part of another medical condition. Oral forms — including tablets, capsules, and oral solution — are used for anxiety relief and to manage itching (pruritus) caused by allergic conditions such as chronic urticaria (hives), atopic dermatitis, contact dermatitis, and histamine-driven itch. Oral forms are also used as a sedative before and after surgery or general anesthesia.

Hydroxyzine Hydrochloride intramuscular injection is used specifically when a shot is needed — for example, in acute psychiatric or emotional emergencies, acute alcohol withdrawal with anxiety symptoms or delirium tremens, control of nausea and vomiting (except during pregnancy), and as pre- and post-operative or pre- and post-partum supportive medication to reduce narcotic requirements and control nausea.

Most-Reported Side Effects for Hydroxyzine

From FAERS, the FDA’s public side-effect reporting system (50,845 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Pruritus 3,383 reports

Nausea 3,067 reports

Fatigue 2,961 reports

Toxicity to various agents 2,567 reports

Completed suicide 2,544 reports

See full Hydroxyzine drug information

Keep checking

Other Drugs & Casein Peptides

Browse every other medication we’ve checked against Casein Peptides — 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 Casein Peptides page.

No interaction 2,657 drugs checked — show the list

We also checked Casein Peptides 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 Casein Peptides list.

See the full Casein Peptides interactions page

See every supplement checked against Hydroxyzine, ranked by severity

Evidence & sources

Casein Peptides References

The 4 references that drive our Casein Peptides 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.

Cicero AFG, Aubin F, Azais-Braesco V, Borghi C. Do the lactotripeptides isoleucine-proline-proline and valine-proline-proline reduce systolic blood pressure in European subjects? A meta-analysis of randomized controlled trials. Am J Hypertens. 2013;26(3): PubMed
Fekete AA, Givens DA, Lovegrove JA. Casein-derived lactotripeptides reduce systolic and diastolic blood pressure in a meta-analysis of randomised clinical trials. Nutrients. 2015;7(1):659-81. PubMed
Qin LQ, Xu JY, Dong JY, Zhao Y, van Bladeren P, Zhang W. Lactotripeptides intake and blood pressure management: a meta-analysis of randomised controlled clinical trials. Nutr Metab Cardiovasc Dis. 2013;23(5):395-402. PubMed
Turpeinen AM, Järvenpää S, Kautiainen H, Korpela R, Vapaatalo H. Antihypertensive effects of bioactive tripeptides-a random effects meta-analysis. Ann Med. 2013;45(1):51-6. 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 Casein Peptides and Hydroxyzine Together: Common Questions

Is it safe to take Casein Peptides with Hydroxyzine?

We do not list a known interaction between Casein Peptides and Hydroxyzine. 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 Casein Peptides and Hydroxyzine 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 Casein Peptides in each. That is a conversation for your prescriber, especially if Hydroxyzine is being adjusted to a target.

How was the Casein Peptides and Hydroxyzine combination checked?

Interactions in our licensed database are recorded against drug classes. Hydroxyzine is filed under 5 classifications, and Casein Peptides has documented interactions with 1 drug class — none of Hydroxyzine'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 Casein Peptides interact with any other medications?

Yes. Casein Peptides has 172 documented drug interactions in our database — Hydroxyzine 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 Hydroxyzine interact with any supplements?

Yes. Hydroxyzine has documented interactions with 183 supplements in our database — Casein Peptides is not one of them. The Hydroxyzine 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

Casein Peptides monograph Uses, safety profile, and every drug interaction in one place Hydroxyzine drug information The full plain-English guide to this medication Hydroxyzine supplement interactions Every supplement checked against Hydroxyzine, 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 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Hydroxyzine and Casein Peptides?

Our pharmacists answer your medication & supplement questions — free.

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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.