Drug & supplement interaction

Piracetam + Cephalexin

Cephalexin brand names: Keflex, Keftab, Cephalex, Lexin.

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 Piracetam and Cephalexin 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

Piracetam and Cephalexin

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 Cephalexin and Piracetam 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.

Piracetam safety at a glance

Piracetam overall Use caution It is a drug, not a true dietary supplement, and is unapproved in the U.S. with variable product quality.
Pregnancy Avoid There is not enough safety data, so avoid use during pregnancy.
Breastfeeding Avoid It may pass into breast milk and safety is unknown, so avoid use while breastfeeding.

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

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

Why No Interaction Is Listed for Cephalexin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Cephalexin is filed under 7 classifications — including organic anion transporter 3 (oat3) substrates, organic anion transporter 1 (oat1) substrates, antibiotic drugs. Piracetam has documented interactions with 1 drug class — the most serious being anticoagulant/antiplatelet drugs (major) — and none of Cephalexin’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

Piracetam Does Interact With Other Medications

Piracetam has 122 major, known drug interactions in our database — Cephalexin isn’t one of them. If you take anything else, check it against the full list below.

Major 122 No known interaction 2,708 (incl. Cephalexin)
Taking anything else?

Check Another of Your Medications Against Piracetam

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

What to actually watch for

No Interaction Found — But Data Suggests Piracetam and Cephalexin 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. 2 of them are worth acting on rather than waiting out — marked below.

  • Confusion Worth acting on Additional detail

    Piracetam

    “Orally, piracetam can cause neurologic symptoms. Short-term use has been rarely reported to cause drowsiness, dizziness, agitation, nervousness, anxiety, weakness, hyperkinesia, mild to moderate symptoms of depression, headache, slurred speech, behavioral changes including irritation and disinhibited behavior, confusion, lethargy, and sleep disturbance.

    In one case report, a 10-year old male with hypothyroidism takin…”

    Piracetam · Natural Medicines adverse-effect record, reported in anxiety.

    6 sources cited
    1. 95170. Malykh AG, Sadaie MR. Piracetam and piracetam-like drugs: from basic science to novel clinical applications to CNS disorders. Drugs 2010;70(3):287-312. PubMed
    2. 95181. Koskiniemi M, Van Vleymen B, Hakamies L, et al. Piracetam relieves symptoms in progressive myoclonus epilepsy: a multicentre, randomised, double blind, crossover study comparing the efficacy and safety of three dosages of oral piracetam with placebo. J Ne PubMed
    3. 95182. Fedi M, Reutens D, Dubeau F, et al. Long-term efficacy and safety of piracetam in the treatment of progressive myoclonus epilepsy. Arch Neurol 2001;58(5):781-6. PubMed
    4. 95183. Wilsher CR, Bennett D, Chase CH, et al. Piracetam and dyslexia: effects on reading tests. J Clin Psychopharmacol 1987;7(4):230-7. DOI
    5. 95186. Winblad B. Piracetam: a review of pharmacological properties and clinical uses. CNS Drug Rev. 2005;11(2):169-82. PubMed
    6. 95188. Neznamov GG, Teleshova ES. Comparative studies of Noopept and piracetam in the treatment of patients with mild cognitive disorders in organic brain diseases of vascular and traumatic origin. Neurosci Behav Physiol. 2009;39(3):311-21. PubMed

    Cephalexin

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

  • Bleeding or bruising Worth acting on Additional detail

    Piracetam

    “Orally, piracetam was reported to cause abnormally heavy menstrual bleeding in one adult.”

    Piracetam · Natural Medicines adverse-effect record, reported in bleeding.

    1 source cited
    1. 95177. Kampman K, Majewska MD, Tourian K, et al. A pilot trial of piracetam and ginkgo biloba for the treatment of cocaine dependence. Addict Behav 2003;28(3):437-48. PubMed

    Cephalexin

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

  • Anxiety or restlessness / Dizziness Additional detail

    Piracetam

    “Orally, piracetam seems to be generally well tolerated.

    Most Common Adverse Effects:

    Orally: Constipation, gastrointestinal disturbances, hypertension, rash, weight gain.

    Serious Adverse Effects (Rare):

    Orally: Agitation, anxiety, behavioral changes, dizziness, drowsiness, hyperkinesia, sleep disturbance, slurred speech.

    Intravenously: Dizziness, weakness.”

    Piracetam · Natural Medicines adverse-effect record, reported in anxiety.

    Cephalexin

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

  • Stomach upset Additional detail

    Piracetam

    “Orally, piracetam has been rarely reported to cause gastrointestinal disturbances, such as nausea, vomiting, constipation, and burning sensation in the mouth.”

    Piracetam · Natural Medicines adverse-effect record, reported in constipation.

    3 sources cited
    1. 95181. Koskiniemi M, Van Vleymen B, Hakamies L, et al. Piracetam relieves symptoms in progressive myoclonus epilepsy: a multicentre, randomised, double blind, crossover study comparing the efficacy and safety of three dosages of oral piracetam with placebo. J Ne PubMed
    2. 95188. Neznamov GG, Teleshova ES. Comparative studies of Noopept and piracetam in the treatment of patients with mild cognitive disorders in organic brain diseases of vascular and traumatic origin. Neurosci Behav Physiol. 2009;39(3):311-21. PubMed
    3. 95246. Croisile B, Trillet M, Fondarai J, Laurent B, Mauguière F, Billardon M. Long-term and high-dose piracetam treatment of Alzheimer's disease. Neurology. 1993;43(2):301-5. PubMed

    Cephalexin

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

  • Tiredness / Headache Additional detail

    Piracetam

    Recorded for Piracetam in the same Natural Medicines adverse-effect record shown under Confusion above.

    Cephalexin

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

  • Vomiting / Nausea Additional detail

    Piracetam

    Recorded for Piracetam in the same Natural Medicines adverse-effect record shown under Stomach upset above.

    Cephalexin

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

Reported for Piracetam but not commonly for Cephalexin: trouble sleeping, a change in thyroid levels, constipation and mood changes or irritability.

Effects for Cephalexin come from the ADVERSE REACTIONS section of its FDA label; effects for Piracetam come from the Natural Medicines adverse-effect record, quoted above. 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 Piracetam or Cephalexin

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

This page covers Piracetam only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Cephalexin page lists 61 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 · 47 moderate · 11 minor.

From our pharmacist’s overview on the Cephalexin page

“Cephalexin (Keflex) is one of the most commonly prescribed oral antibiotics, usually for skin and urinary infections, and its supplement list warrants genuine care rather than a quick skim. Three of the 61 ingredients on file rate major.”

Reviewed by 2 · Jul 18, 2026

Open the Cephalexin interaction page

One more smart check

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

We hold 6 real supplement products containing Piracetam, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Piracetam. Even though Piracetam itself has no known interaction with Cephalexin, 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 Piracetam and Cephalexin 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 Piracetam
Steady interest

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

29 days ago today
Medication Cephalexin
Top 5%

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

What is Piracetam?

  • Memory and cognition ('nootropic')
  • Cognitive decline and dementia
  • Myoclonus
  • Dyslexia in children
  • Vertigo

Piracetam is a synthetic 'nootropic' drug studied mainly for cognitive decline, myoclonus, and certain neurological conditions, but evidence for boosting memory in healthy people is weak. It is a prescription medicine in many countries and is not an approved drug or dietary supplement in the United States, so quality and safety of products sold online vary. Talk to a doctor or pharmacist before using it.

Synthetic compound (not plant-derived) · Tablets, capsules, powder, oral solution

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

Piracetam: dosing

There is no established 'supplement' dose for piracetam, and recommended amounts in medical settings vary widely depending on the country and condition being treated. Because it is unapproved in the U.S. They can help you weigh the risks, especially if you have kidney issues or take other medicines. Do not assume that taking more will work better; higher amounts may increase side effects.

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

Read the full Piracetam monograph & all interactions
Medication

About Cephalexin

What Is Cephalexin Used For?

Brand names: Keflex, Keftab, Cephalex, Lexin

Cephalexin treats bacterial infections caused by susceptible strains of bacteria. It is used for respiratory tract infections, ear infections (otitis media), skin and skin structure infections, bone infections, and genitourinary tract infections — including acute prostatitis.

It works only against bacterial infections — not viruses like colds or flu. Your prescriber should use it only when a bacterial infection is confirmed or strongly suspected, to help prevent antibiotic resistance.

Most-Reported Side Effects for Cephalexin

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.

Chronic kidney disease 2,157 reports
Renal failure 1,558 reports
Acute kidney injury 1,550 reports
Diarrhea 1,405 reports
Fatigue 1,303 reports
See full Cephalexin drug information
Keep checking

Other Drugs & Piracetam

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

122Major
0Moderate
0Minor
2,707No known interaction
122 Major 2,707 No interaction
Major

122 interactions

Showing 60 of 122 major interactions — see all 122 on the Piracetam page.

No interaction 2,707 drugs checked — show the list

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

Showing the 60 most looked-up of 2,707 medications checked with no known interaction — see the full Piracetam list.

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

Piracetam References

The 16 references that drive our Piracetam 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. Malykh AG, Sadaie MR. Piracetam and piracetam-like drugs: from basic science to novel clinical applications to CNS disorders. Drugs 2010;70(3):287-312. PubMed
  2. Ozdemir H, Akinci E, Coskun F. Comparison of the effectiveness of intravenous piracetam and intravenous dimenhydrinate in the treatment of acute peripheral vertigo in the emergency department. Singapore Med J 2013;54(11):649-52. PubMed
  3. Kampman K, Majewska MD, Tourian K, et al. A pilot trial of piracetam and ginkgo biloba for the treatment of cocaine dependence. Addict Behav 2003;28(3):437-48. PubMed
  4. Koskiniemi M, Van Vleymen B, Hakamies L, et al. Piracetam relieves symptoms in progressive myoclonus epilepsy: a multicentre, randomised, double blind, crossover study comparing the efficacy and safety of three dosages of oral piracetam with placebo. J Ne PubMed
  5. Fedi M, Reutens D, Dubeau F, et al. Long-term efficacy and safety of piracetam in the treatment of progressive myoclonus epilepsy. Arch Neurol 2001;58(5):781-6. PubMed
  6. Wilsher CR, Bennett D, Chase CH, et al. Piracetam and dyslexia: effects on reading tests. J Clin Psychopharmacol 1987;7(4):230-7. DOI
  7. Di Ianni M, Wilsher CR, Blank MS, et al. The effects of piracetam in children with dyslexia. J Clin Psychopharmacol. 1985;5(5):272-8. PubMed
  8. Winblad B. Piracetam: a review of pharmacological properties and clinical uses. CNS Drug Rev. 2005;11(2):169-82. PubMed
  9. Neznamov GG, Teleshova ES. Comparative studies of Noopept and piracetam in the treatment of patients with mild cognitive disorders in organic brain diseases of vascular and traumatic origin. Neurosci Behav Physiol. 2009;39(3):311-21. PubMed
  10. Moriau M, Crasborn L, Lavenne-Pardonge E, et al. Platelet anti-aggregant and rheological properties of piracetam. A pharmacodynamic study in normal subjects. Arzneimittelforschung. 1993;43(2):110-8.
  11. Rao MG, Holla B, Varambally S, et al. Piracetam treatment in patients with cognitive impairment. Gen Hosp Psychiatry. 2013;35(4):451.e5-6. PubMed
  12. Tuncer S, Sencan A, Aral M, Ayhan S. Piracetam-induced dysarthria: an unusual complication of antithrombotic prophylaxis after toe to finger transfer. J Reconstr Microsurg. 2011;27(9):575-6. PubMed
  13. Waters B, Resnick M, Simeon J, et al. An adverse reaction to piracetam in an hypothyroid 10 year old boy. Prog Neuropsychopharmacol. 1980;4(2):207-9. PubMed
  14. Sandyk R, Gillman MA. Piracetam causes confusion in a patient with temporal lobe epilepsy. J Am Geriatr Soc. 1985;33(4):305. PubMed
  15. Croisile B, Trillet M, Fondarai J, Laurent B, Mauguière F, Billardon M. Long-term and high-dose piracetam treatment of Alzheimer's disease. Neurology. 1993;43(2):301-5. 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 Piracetam and Cephalexin Together: Common Questions

Is it safe to take Piracetam with Cephalexin?
We do not list a known interaction between Piracetam and Cephalexin. 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 Piracetam and Cephalexin have any of the same side effects?
Yes — our sources link each of them separately to 9 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 Piracetam and Cephalexin combination checked?
Interactions in our licensed database are recorded against drug classes. Cephalexin is filed under 7 classifications, and Piracetam has documented interactions with 1 drug class — none of Cephalexin'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 Piracetam interact with any other medications?
Yes. Piracetam has 122 documented drug interactions in our database — Cephalexin 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 Cephalexin interact with any supplements?
Yes. Cephalexin has documented interactions with 61 supplements in our database — Piracetam is not one of them. The Cephalexin 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

Piracetam monograph Uses, safety profile, and every drug interaction in one place Cephalexin drug information The full plain-English guide to this medication Cephalexin supplement interactions Every supplement checked against Cephalexin, 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 16 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Cephalexin and Piracetam?

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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.