Drug Interaction Report

Desloratadine and Gemfibrozil: Interaction Details

A pharmacist-reviewed analysis of the Desloratadine and Gemfibrozil interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Desloratadine

Clarinex Clarinex® Clarinex® Reditabs®
+

Gemfibrozil

Lopid Lopid®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 9 documented Desloratadine interactions, 9 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
probable
Severity
Major

What happens

Increased desloratadine exposure

Interaction Deep Dive

Coadministration of gemfibrozil, a strong CYP2C8 inhibitor, may increase exposure of certain CYP2C8 substrates1, such as desloratadine. In a study, coadministration of desloratadine and gemfibrozil increased the desloratadine AUC by 462% and Cmax by 174% compared with desloratadine and placebo 2. If coadministration is required, a decreased dosage of the CYP2C8 substrate may be necessary 1.

Why it happens (mechanism)

Inhibition of CYP2C8-mediated metabolism by gemfibrozil

Literature reports

1 report — tap to read

a) Coadministration of desloratadine and gemfibrozil increased desloratadine AUC(0 to infinity) by 462% (90% CI, 346% to 616%) and Cmax by 174% (90% CI, 137% to 221%) compared with desloratadine and placebo in a randomized crossover study of healthy, nonsmoking volunteers (N=11); half-life was also prolonged from 17 to 39 hours. During the gemfibrozil phase of the study, patients received gemfibrozil 600 mg twice daily on days 1 through 5, and a single dose of desloratadine 5 mg was administered on day 3. Gemfibrozil is a CYP2C8 inhibitor, and the results suggest that the in vivo metabolism of desloratadine to 3-hydroxydesloratadine (metabolite) is highly dependent on CYP2C8 2.

Common questions

Can I take Desloratadine and Gemfibrozil together?

Increased desloratadine exposure Always confirm with your pharmacist or prescriber before making any change.

How serious is the Desloratadine and Gemfibrozil interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

How strong is the evidence for this interaction?

The evidence is graded "probable". Good supporting evidence, though not definitively proven.

Questions for your pharmacist

  • Does my dose of Desloratadine or Gemfibrozil need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there a safer alternative to one of these medications for me?

References (2)

  1. Product Information: LOPID(R) oral tablets, gemfibrozil oral tablets. Parke-Davis (per manufacturer), New York, NY, 2018. DailyMed
  2. Itkonen MK, Tornio A, Neuvonen M, et al: Clopidogrel and gemfibrozil strongly inhibit the CYP2C8-dependent formation of 3-hydroxydesloratadine and increase desloratadine exposure in humans. Drug Metab Dispos 2019; 47(4):377-385. PubMed
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Desloratadine

Keep reading about Desloratadine

All Desloratadine interactions (9) Desloratadine drug information
Also serious with: Abiraterone Clopidogrel Abiraterone Acetate Abiraterone Acetate, Micronized
Gemfibrozil

Keep reading about Gemfibrozil

All Gemfibrozil interactions (80) Gemfibrozil drug information
Also serious with: Grazoprevir Ciprofibrate Dasabuvir Elagolix
Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Desloratadine + Activated Charcoal Biofeedback Coffee Charcoal Dendrobium European Mandrake Ginkgo Glucomannan Guar Gum + 15 more
Gemfibrozil + Activated Charcoal Beer Siberian Cocklebur Wine Ashwagandha Black Cohosh Boldo Buchu + 51 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.