Ketotifen
ZADITOR
Pronunciation: kee-toe-TYE-fen
What it isH1 antagonist with mast-cell stabilization; allergic conjunctivitis.
Why this oneIts inexpensive over-the-counter eye drops combine immediate antihistamine relief with prevention of further mediator release.
What limits itLocal burning or irritation can stop use; oral ketotifen, used outside the US, is sedating.
Ketotifen prescription history
Animated chart of estimated U.S. prescriptions per year, H1 antihistamines (1944–2026). Ketotifen enters in 1999 (estimated).
FDA-approved for
- allergic conjunctivitis (1999)
Principal riskLocal irritation
Classes and tags
Clinical profile
Legacy pregnancy categoryNot assigned — OTC/monograph
Defining liabilityLocal irritation, sensitization or administration-site injury; negligible systemic toxicity at usual use.
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Eye itch due to allergy | adults & children ≥3 yr | 1 drop in affected eye(s) BID (q8-12h) | no more than twice per day |
Renal Undefined
Hepatic Undefined
Instructions
- If using other ophthalmic products, wait at least 5 minutes between each product
- Children under 3 yr: consult a doctor
Available strengths
- drops 0.025 %
- sol 0.25, 0.35 mg/mL
Pregnancy Undefined
Lactation Undefined
Cost
| Strength | #/mo | generic $/unit | CostPlus | |
|---|---|---|---|---|
| 0.025 % | drops | per unit | not offered |
Generic entry2012
Open Ketotifen in the interactive console ↗
Self-check
- What action complements ketotifen’s immediate H1 blockade?
Mast-cell stabilization. - What limits oral ketotifen used outside the US?
Sedation.