Cilostazol and Esomeprazole: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cilostazol
Esomeprazole
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.
What happens
Increased cilostazol exposure
Interaction Deep Dive
Cilostazol exposure is increased with coadministration of CYP2C19 inhibitors2. Coadministration of cilostazol with omeprazole (a CYP2C19 inhibitor) increased the concentrations of cilostazol and it's active metabolites by 26% to 69% 3. When coadministration of cilostazol with a CYP2C19 inhibitor is required, consider reducing the cilostazol dose to 50 mg twice daily 21.
Why it happens (mechanism)
Inhibition of CYP2C19-mediated metabolism of cilostazol
Literature reports
2 reports — tap to read
a) Coadministration of omeprazole and cilostazol 100 mg increased the AUC of the pharmacologically-active 3,4-dehydro-cilostazol metabolite by 69% 2.
b) Concomitant use of cilostazol, a CYP2C19 substrate, and omeprazole, a CYP2C19 inhibitor, resulted in increased plasma concentrations of cilostazol and one of its active metabolites. Twenty healthy nonsmoking volunteers participated in a single-center, open-label study to evaluate the effect of omeprazole on the pharmacokinetics of a single dose of cilostazol 100 mg. Each study subject received cilostazol 100 mg on day 0 under fasting conditions. On days 7 through 18, omeprazole 40 mg was given each morning. Another single dose of cilostazol 100 mg was administered with omeprazole on day 14 3. After omeprazole administration, the Cmax of cilostazol increased by 18% (from 782 mcg/L to 921 mcg/L) and the AUC increased by 26% (from 10,287 mcg/L/h to 13,033 mcg/L/hr). The mean Cmax of OPC-13015, a pharmacologically active metabolite of cilostazol, increased by 29% and the AUC increased by 69% in the presence of omeprazole 31. Conversely, the Cmax and AUC of OPC-13213, another pharmacologically active metabolite of cilostazol, decreased by 22% and 31%, respectively. Although the changes in systemic exposure to cilostazol were well tolerated, the dose of cilostazol should be reduced to 50 mg twice daily when given concurrently with omeprazole 3.
Common questions
Can I take Cilostazol and Esomeprazole together?
Increased cilostazol exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Cilostazol and Esomeprazole 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Cilostazol or Esomeprazole 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 (3)
- Product Information: KONVOMEP(TM) powder for oral suspension, omeprazole sodium bicarbonate powder for oral suspension. Azurity Pharmaceuticals Inc (per manufacturer), Woburn, MA, 2022. DailyMed
- Product Information: PLETAL(R) oral tablets, cilostazol oral tablets. Otsuka America Pharmaceutical, Inc. (per FDA), Rockville, MD, 2015. DailyMed
- Suri A & Bramer SL: Effect of omeprazole on the metabolism of cilostazol. Clin Pharmacokinet 1999; 37(suppl 2):53-59. PubMed
Keep reading about Cilostazol
Keep reading about Esomeprazole
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:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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