Drug & supplement interaction

Lysine + Cefprozil

Cefprozil brand name: Cefzil.

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 Lysine and Cefprozil 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

Lysine and Cefprozil

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 Cefprozil and Lysine 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.

Lysine safety at a glance

Lysine overall Use caution Generally well tolerated at typical doses, but high amounts may cause stomach upset and long-term safety is not well studied.
Pregnancy Use caution Lysine from food is fine, but supplement safety in pregnancy is not well studied, so check with your doctor first.
Breastfeeding Use caution There is not enough reliable information on supplement use while breastfeeding, so caution is advised.

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

Still wondering about combining Cefprozil and Lysine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Cefprozil

Interactions in our licensed database are recorded against drug classes, not just single drug names. Cefprozil is filed under 6 classifications — including organic anion transporter 3 (oat3) substrates, organic anion transporter 1 (oat1) substrates, antibiotic drugs. Lysine has documented interactions with 1 drug class — the most serious being 5-ht4 agonists (minor) — and none of Cefprozil’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

Lysine Does Interact With Other Medications

Lysine has 1 minor known drug interaction in our database — Cefprozil isn’t one of them. If you take anything else, check it against the full list below.

Minor 1 No known interaction 2,829 (incl. Cefprozil)
Taking anything else?

Check Another of Your Medications Against Lysine

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

What to actually watch for

No Interaction Found — But Data Suggests Lysine and Cefprozil 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 / Diarrhea Additional detail

    Lysine

    “Orally, lysine has been reported to cause diarrhea and abdominal pain, including dyspepsia.”

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

    5 sources cited
    1. 1114. Thein DJ, Hurt WC. Lysine as a prophylactic agent in the treatment of recurrent herpes simplex labialis. Oral Surg Oral Med Oral Pathol 1984;58:659-66. PubMed
    2. 1115. McCune MA, Perry HO, Muller SA, O'Fallon WM. Treatment of recurrent herpes simplex infections with L-lysine monohydrochloride. Cutis 1984;34:366-73.
    3. 1116. DiGiovanna JJ, Blank H. Failure of lysine in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Arch Dermatol 1984;120:48-51. DOI
    4. 1118. Milman N, Scheibel J, Jessen O. Lysine prophylaxis in recurrent herpes simplex labialis: a double-blind, controlled crossover study. Acta Derm Venereol 1980;60:85-7.
    5. 1120. Griffith RS, Walsh DE, Myrmel KH, et al. Success of L-lysine therapy in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Dermatologica 1987;175:183-90. DOI

    Cefprozil

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

Reported for Lysine but not commonly for Cefprozil: kidney problems and stomach upset.

Effects for Cefprozil come from the ADVERSE REACTIONS section of its FDA label; effects for Lysine come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 780 voluntary FDA FAERS reports for Cefprozil 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.

From our Q&A

Questions About Lysine or Cefprozil

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

This page covers Lysine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cefprozil page lists 60 supplements it has a documented interaction with, worst first, each one explained.

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

By severity: 3 major · 46 moderate · 11 minor.

From our pharmacist’s overview on the Cefprozil page

“Cefprozil (Cefzil) is a cephalosporin antibiotic, usually a short course for ear, sinus, throat, or skin infections, and three of the 60 supplements on this list warrant real caution even for a week of pills. Activated charcoal can bind the drug and pull it out of your system before it works.”

Reviewed by 2 · Jul 18, 2026

Open the Cefprozil interaction page

One more smart check

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

We hold 3,540 real supplement products containing Lysine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lysine. Even though Lysine itself has no known interaction with Cefprozil, 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 Lysine and Cefprozil 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 Lysine
Top 5%

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

29 days ago today
Medication Cefprozil
Steady interest

#1,986 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 Lysine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Lysine and Cefprozil 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 Lysine

What is Lysine?

  • Cold sores (herpes labialis)
  • Genital herpes outbreaks
  • Supporting protein and collagen formation
  • Calcium absorption support
  • General nutritional supplement

Lysine is an essential amino acid your body cannot make on its own, so it must come from food or supplements. People most often take extra lysine to try to prevent or shorten cold sores, but the evidence is mixed and far from conclusive. For most healthy people who eat enough protein, supplements are likely unnecessary, but they are generally considered low-risk at typical doses.

Amino acid (L-lysine) · Tablets, capsules, powder, topical creams (often combined with other ingredients)

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

Lysine: dosing

There is no single official supplement dose of lysine for any health condition, and a truly standardized dose has not been established for uses like cold sores. Products vary widely in how much they contain.The best approach is to follow the directions on the product label and not exceed the recommended amount.

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

Read the full Lysine monograph & all interactions
Medication

About Cefprozil

What Is Cefprozil Used For?

Brand name: Cefzil

Cefprozil tablets and oral suspension are both used to treat mild to moderate bacterial infections in adults and children. Approved uses include pharyngitis/tonsillitis (strep throat), acute sinusitis, otitis media (ear infections), acute bacterial exacerbation of chronic bronchitis, and uncomplicated skin and skin-structure infections.

Cefprozil tablets are also approved for secondary bacterial infection of acute bronchitis. Because antibiotic resistance is a real concern, cefprozil should only be used when the infection is proven or strongly suspected to be caused by bacteria that respond to it.

Most-Reported Side Effects for Cefprozil

From FAERS, the FDA’s public side-effect reporting system (780 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Chronic kidney disease 89 reports
Drug hypersensitivity 73 reports
Cough 64 reports
Acute kidney injury 59 reports
Dyspnea 59 reports
See full Cefprozil drug information
Keep checking

Other Drugs & Lysine

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

0Major
0Moderate
1Minor
2,828No known interaction
1 Minor 2,828 No interaction
Minor

1 interaction

No interaction 2,828 drugs checked — show the list

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

Showing the 60 most looked-up of 2,828 medications checked with no known interaction — see the full Lysine list.

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

Lysine References

The 7 references that drive our Lysine 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. Thein DJ, Hurt WC. Lysine as a prophylactic agent in the treatment of recurrent herpes simplex labialis. Oral Surg Oral Med Oral Pathol 1984;58:659-66. PubMed
  2. McCune MA, Perry HO, Muller SA, O'Fallon WM. Treatment of recurrent herpes simplex infections with L-lysine monohydrochloride. Cutis 1984;34:366-73.
  3. DiGiovanna JJ, Blank H. Failure of lysine in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Arch Dermatol 1984;120:48-51. DOI
  4. Milman N, Scheibel J, Jessen O. Lysine prophylaxis in recurrent herpes simplex labialis: a double-blind, controlled crossover study. Acta Derm Venereol 1980;60:85-7.
  5. Griffith RS, Walsh DE, Myrmel KH, et al. Success of L-lysine therapy in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Dermatologica 1987;175:183-90. DOI
  6. Lo JC, Chertow GM, Rennke H, Seifter JL. Fanconi's syndrome and tubulointerstitial nephritis in association with L-lysine ingestion. Am J Kidney Dis 1996;28:614-7. PubMed
  7. Smriga M, Torii K. L-Lysine acts like a partial serotonin receptor 4 antagonist and inhibits serotonin-mediated intestinal pathologies and anxiety in rats. Proc Natl Acad Sci U S A. 2003 Dec 23;100(26):15370-5.

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 Lysine and Cefprozil Together: Common Questions

Is it safe to take Lysine with Cefprozil?
We do not list a known interaction between Lysine and Cefprozil. 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 Lysine and Cefprozil 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.
How was the Lysine and Cefprozil combination checked?
Interactions in our licensed database are recorded against drug classes. Cefprozil is filed under 6 classifications, and Lysine has documented interactions with 1 drug class — none of Cefprozil'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 Lysine interact with any other medications?
Yes. Lysine has 1 documented drug interaction in our database — Cefprozil 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 Cefprozil interact with any supplements?
Yes. Cefprozil has documented interactions with 60 supplements in our database — Lysine is not one of them. The Cefprozil 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

Lysine monograph Uses, safety profile, and every drug interaction in one place Cefprozil drug information The full plain-English guide to this medication Cefprozil supplement interactions Every supplement checked against Cefprozil, 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 7 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Cefprozil and Lysine?

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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.