Allegra and Zaditor drug interactions - a phase IV clinical study of FDA data

Summary:

Drug interactions are reported among people who take Allegra (fexofenadine hydrochloride) and Zaditor (ketotifen fumarate). Common drug interactions include abdominal pain upper among females and abnormal behaviour among males.

The phase IV clinical study analyzes what interactions people have when they take Allegra and Zaditor. It is created by eHealthMe based on reports of 65 people who take the same drugs from the FDA, and is updated regularly.

What is Allegra?

Allegra has active ingredients of fexofenadine hydrochloride. It is often used in allergies. eHealthMe is studying from 75,497 Allegra users. Check the latest studies of Allegra.

What is Zaditor?

Zaditor has active ingredients of ketotifen fumarate. It is often used in eye allergy. eHealthMe is studying from 4,448 Zaditor users. Check the latest studies of Zaditor.

On Jul, 07, 2026

65 people who take Allegra and Zaditor together, and have interactions are studied.

What are the common drug interactions of Allegra and Zaditor, by gender? *:

female:

Abdominal pain upper
Arthralgia (joint pain)
Burning sensation
Cough
Dacryostenosis acquired (obstruction of the nasolacrimal duct-acquired)
Drug dependence
Drug hypersensitivity
Dysgeusia (disorder of the sense of taste)
Epstein-barr virus infection
Erythema of eyelid (redness of the eyelid)

male:

Abnormal behaviour
Malaise (a feeling of general discomfort or uneasiness)
Disturbance in attention
Dyspepsia (indigestion)
Erectile dysfunction
Facial pain
Fatigue (feeling of tiredness)
Haemorrhoids (a swollen vein or group of veins in the region of the anus)
Injury
Insomnia (sleeplessness)

What are the common drug interactions of Allegra and Zaditor, by age (0-1 to 60+)? *:

0-1:

n/a

2-9:

n/a

10-19:

n/a

20-29:

Anaphylactic reaction (serious allergic reaction)
Eye pruritus (eye itching)
Nasal congestion (blockage of the nasal passages usually due to membranes lining the nose becoming swollen from inflamed blood vessels)
Antinuclear antibody positive
Antiphospholipid antibodies positive
Cardiolipin antibody positive
Cervical dysplasia (abnormal changes in the cells on the surface of the cervix)
Chest discomfort
Chest pain
Convulsion (muscles contract and relax rapidly and repeatedly, resulting in an uncontrolled shaking of the body)

30-39:

Constipation
Dyspepsia (indigestion)
Ear pain
Fatigue (feeling of tiredness)
Gastric polyps (abnormal growth of stomach tissue projecting from a mucous membrane)
Gastroenteritis viral (inflammation of stomach and intestine caused by virus infection)
Headache (pain in head)
Irritable bowel syndrome
Nasopharyngitis (inflammation of the nasopharynx)
Rhinitis (a medical term for irritation and inflammation of the mucous membrane inside the nose)

40-49:

Screaming (a long loud piercing cry)
Sinusitis (inflammation of sinus)
Upper respiratory tract infection
Vision blurred
Abnormal behaviour
Hypersensitivity
Optic atrophy (the loss of a proportion of optic disc nerve fibres)
Parkinsonism (degenerative disorder of the central nervous system characterized by tremor and impaired muscular coordination)
Scleral disorder (disease of sclera)
Visual acuity reduced (reduced clearness of vision)

50-59:

Drug ineffective
Insomnia (sleeplessness)
Peripheral swelling
Weight increased
Anaemia (lack of blood)
Anaphylactic reaction (serious allergic reaction)
Arterial stenosis (abnormal narrowing of the aortic valve in the heart)
Arthralgia (joint pain)
Atrial fibrillation (fibrillation of the muscles of the atria of the heart)
Back pain

60+:

Fatigue (feeling of tiredness)
Nausea (feeling of having an urge to vomit)
Spinal compression fracture (fracture due to spinal compression on bone)
Abdominal discomfort
Abdominal pain upper
Blood pressure increased
Burning sensation
Constipation
Dizziness
Drug hypersensitivity

What are the existing conditions these people have? *

Hypersensitivity: 8 people, 12.31%
Narcolepsy (brain's inability to regulate sleep-wake cycles normally): 7 people, 10.77%
Seasonal Allergy (allergic condition due to certain season): 6 people, 9.23%
Primary Immunodeficiency Syndrome: 6 people, 9.23%
Asthma: 6 people, 9.23%
Cataplexy (loss of muscle tone accompanied by full conscious awareness): 5 people, 7.69%
Immunodeficiency: 4 people, 6.15%
Gastroesophageal Reflux Disease (a condition in which stomach contents leak backward from the stomach into the oesophagus): 4 people, 6.15%

* Approximation only. Some reports may have incomplete information.

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