Ketotifen and Pitolisant: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Pitolisant
Ketotifen
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
Reduced efficacy of pitolisant
Interaction Deep Dive
Avoid concomitant use of pitolisant and centrally-acting H1-receptor antagonists. Pitolisant increases the levels of histamine in the brain, therefore histamine H1-receptor antagonists that cross the blood-brain barrier may reduce the effectiveness of pitolisant1.
Why it happens (mechanism)
Interference with mechanism of action of pitolisant
Common questions
Can I take Ketotifen and Pitolisant together?
Reduced efficacy of pitolisant Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ketotifen and Pitolisant 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 Ketotifen or Pitolisant 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 (1)
- Product Information: WAKIX® oral tablets, pitolisant oral tablets. Harmony Biosciences LLC (per FDA), Plymouth Meeting, PA, 2026. DailyMed
Keep reading about Pitolisant
Keep reading about Ketotifen
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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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