Drug & supplement interaction

Khat + Lansoprazole, Amoxicillin, Clarithromycin

Lansoprazole, Amoxicillin, Clarithromycin brand name: Prevpac.

Major Interaction
Medically reviewed by · Updated September 2026
The bottom line Major

Khat has a major interaction with Lansoprazole, Amoxicillin, Clarithromycin. Clinical research shows that chewing khat reduces the bioavailability of amoxicillin when taken within 2 hours.

Read the full interaction report
SeverityMajor
LikelihoodLikely
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Khat and Lansoprazole, Amoxicillin, Clarithromycin

Here is the interaction we found between these two, with the evidence behind it.

Major

AMOXICILLIN (Amoxil, Trimox)

Clinical research shows that chewing khat reduces the bioavailability of amoxicillin when taken within 2 hours. Separate dose times by at least 2 hours.
Severity Major Likelihood Likely Evidence B

Well-controlled human studies have demonstrated the likely existence of this interaction.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the practical issue with this combo. Prevpac is a triple therapy pack (lansoprazole, amoxicillin, and clarithromycin) that's prescribed to knock out an H. pylori stomach infection. The amoxicillin part is the worker bee here, and studies show that chewing khat around the same time can cut down how much amoxicillin your body actually absorbs. Less of the antibiotic getting in means it may not fully clear the bacteria.

That matters because a half-treated infection can come back, and undertreating can encourage resistant bugs. On top of that, khat is a controlled, illegal stimulant with real risks of its own. If khat is somehow part of the picture, please be upfront with your pharmacist or doctor so they can make sure the antibiotic timing and your whole treatment stay on track.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Attef, O. A., Ali, A. A., and Ali, H. M. Effect of Khat chewing on the bioavailability of ampicillin and amoxycillin. J.Antimicrob.Chemother. 1997;39(4):523-525. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Khat Also Interacts With Other Medications

Khat has 3 major, 401 moderate known drug interactions in our database — the Lansoprazole, Amoxicillin, Clarithromycin one above is one of them. If you take anything else, check it against the full list below.

Major 3 Moderate 401 No known interaction 2,426 (incl. Lansoprazole, Amoxicillin, Clarithromycin)
Taking anything else?

Check Another of Your Medications Against Khat

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

Everything else you take

See Every Supplement That Interacts With Lansoprazole, Amoxicillin, Clarithromycin

This page covers Khat only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Lansoprazole, Amoxicillin, Clarithromycin page lists 246 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Asarabacca (major) and Beer (major).

By severity: 14 major · 185 moderate · 47 minor.

From our pharmacist’s overview on the Lansoprazole, Amoxicillin, Clarithromycin page

“Prevpac pairs lansoprazole with two antibiotics, amoxicillin and clarithromycin, to knock out an H. pylori stomach infection, and I treat its supplement list with genuine caution.”

Reviewed by 2 · Jul 18, 2026

Open the Lansoprazole, Amoxicillin, Clarithromycin interaction page

How much people look this up

Where Khat and Lansoprazole, Amoxicillin, Clarithromycin 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 Khat
Top half

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

29 days ago today
Medication Lansoprazole, Amoxicillin, Clarithromycin
Top half

#749 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.

Supplement

About Khat

What is Khat?

Khat
  • Stimulant for energy and alertness
  • Euphoria and mood elevation
  • Reducing fatigue
  • Appetite suppression
  • Social and traditional ceremonies

Khat is a plant chewed for its amphetamine-like stimulant effects, but it carries serious risks including high blood pressure, heart problems, mental health effects, and dependence. It is a controlled substance and illegal in the United States and many other countries, so it should not be used.

Read the full Khat monograph & all interactions
Keep checking

Other Drugs & Khat

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

3Major
401Moderate
0Minor
2,425No known interaction
3 Major 401 Moderate 2,425 No interaction
Major

3 interactions

Moderate

401 interactions

Showing 60 of 401 moderate interactions — see all 401 on the Khat page.

No interaction 2,425 drugs checked — show the list

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

Showing the 60 most looked-up of 2,425 medications checked with no known interaction — see the full Khat list.

See the full Khat interactions page
See every supplement checked against Lansoprazole, Amoxicillin, Clarithromycin, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Khat monograph › Uses, safety, and every drug interaction in one place Lansoprazole, Amoxicillin, Clarithromycin supplement interactions › Every supplement checked against Lansoprazole, Amoxicillin, Clarithromycin, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Khat and Lansoprazole, Amoxicillin, Clarithromycin Together: Common Questions

Can you take Khat with Lansoprazole, Amoxicillin, Clarithromycin?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Khat and Lansoprazole, Amoxicillin, Clarithromycin interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Lansoprazole, Amoxicillin, Clarithromycin and Khat?

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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.