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Ketotifen Side Effects

The most commonly reported side effects of ketotifen include treatment failure, eye irritation, and fatigue, based on 8,476 FDA adverse event reports from 2004 to 2025. 12.2% of reports found the drug to be ineffective.

Ketotifen side effects

Percentages show how often each reaction appears relative to total reports for ketotifen.

1
Treatment Failure35.5%3,009
2
Drug Ineffective12.2%1,037
3
Eye Irritation6.5%548
4
Fatigue3.6%307
5
Pruritus3.6%306
6
Nausea3.3%279
7
Headache3.2%268
8
Urticaria3.1%266
9
Eye Pain3.1%259
10
Diarrhoea2.9%248
11
Hypersensitivity2.9%243
12
Dyspnoea2.8%240
13
Off Label Use2.7%230
14
Dizziness2.6%220
15
Eye Pruritus2.5%216

These are voluntary reports and do not establish that ketotifen caused these reactions.

Report severity

25.3%Serious2,145 reports
10.2%Hospitalizations868 reports
1.3%Fatal112 reports

Seriousness is determined by the reporter, not by OpenClaim.

Ketotifen drug interactions

Other drugs that appear in adverse event reports alongside ketotifen. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Olopatadine-hydrochloride26.1%2,214
2
Azelastine16.4%1,386
3
Cromolyn-sodium11.4%970
4
Epinastine-hydrochloride6.3%535
5
Omalizumab4.5%385
6
Ketorolac-tromethamine4.3%363
7
Montelukast-sodium2.9%245
8
Dupilumab2.0%168
9
Sodium-oxybate1.9%158
10
Cetirizine-hydrochloride1.7%145
11
Cyclosporine1.5%128
12
Ranitidine1.1%97
13
Methotrexate1.1%93
14
Adalimumab1.1%91
15
Prednisone1.1%91

Taken alongside

1
Albuterol9.0%760
2
Montelukast-sodium8.8%749
3
Fluticasone8.4%710
4
Ergocalciferol8.4%710
5
Acetaminophen8.2%694
6
Cetirizine-hydrochloride7.7%652
7
Levothyroxine-sodium6.3%535
8
Diphenhydramine5.5%464
9
Aspirin5.4%459
10
Epinephrine5.2%441
11
Famotidine5.1%435
12
Prednisone5.0%424
13
Omeprazole4.8%404
14
Loratadine4.2%358
15
Ondansetron3.9%331

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports ketotifen side effects

68.1% of ketotifen adverse event reports involve female patients and 25.3% involve male patients. The largest age group is adult at 55%. These figures reflect who reports side effects, not underlying risk.

Sex

Female68.1%
Male25.3%
Unknown6.7%

Age group

< 20.9%
2–114.7%
12–171.9%
18–6455.2%
65+37.3%

What is ketotifen used for

Conditions and purposes for which patients were taking ketotifen when the adverse event was reported.

AcneAdverse EventAllergy ProphylaxisAllergy To AnimalAllergy To PlantsAnaphylactic ReactionAngioedemaAntiallergic TherapyAntifungal TreatmentAsthenopiaAsthmaAsthma ProphylaxisAcute Generalised Exanthematous PustulosisAllergy To AnimalAnaphylactic Reaction

Showing 15 of 222 indications

Ketotifen brand names and reporting trend

Ketotifen is sold under the brand name Zaditor.

Brand names

Zaditor21

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking ketotifen with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.