OpenClaim

Zileuton Side Effects

The most commonly reported side effects of zileuton include asthma, dyspnoea, and off label use, based on 806 FDA adverse event reports from 2004 to 2025. 5.3% of reports found the drug to be ineffective.

Zileuton side effects

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

1
Asthma9.1%73
2
Dyspnoea5.3%43
3
Drug Ineffective5.3%43
4
Off Label Use5.1%41
5
Headache4.0%32
6
Nausea4.0%32
7
Pneumonia3.8%31
8
Fatigue3.5%28
9
Dyspnoea3.2%26
10
Product Use In Unapproved Indication3.2%26
11
Cough2.9%23
12
Anaphylactic Reaction2.7%22
13
Alanine Aminotransferase Increased2.6%21
14
Sinusitis2.6%21
15
Malaise2.5%20

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

Report severity

57.8%Serious466 reports
25.6%Hospitalizations206 reports
3.7%Fatal30 reports

Seriousness is determined by the reporter, not by OpenClaim.

Zileuton drug interactions

Other drugs that appear in adverse event reports alongside zileuton. 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
Omalizumab19.7%159
2
Dupilumab10.9%88
3
Sodium-oxybate4.0%32
4
Fluticasone3.3%27
5
Montelukast-sodium3.3%27
6
Prednisone3.2%26
7
Salmeterol-xinafoate2.7%22
8
Mepolizumab2.6%21
9
Tiotropium-bromide1.9%15
10
Budesonide1.6%13
11
Carboplatin1.5%12
12
Gemcitabine1.5%12
13
Albuterol1.5%12
14
Cetirizine-hydrochloride1.4%11
15
Adalimumab1.4%11

Taken alongside

1
Albuterol38.6%311
2
Fluticasone33.9%273
3
Prednisone26.8%216
4
Montelukast-sodium21.8%176
5
Budesonide20.5%165
6
Salmeterol-xinafoate19.5%157
7
Formoterol18.2%147
8
Ergocalciferol17.1%138
9
Cetirizine-hydrochloride15.9%128
10
Acetaminophen15.6%126
11
Epinephrine14.6%118
12
Tiotropium-bromide14.4%116
13
Mometasone-furoate14.0%113
14
Levothyroxine-sodium13.6%110
15
Fexofenadine-hydrochloride13.5%109

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 zileuton side effects

63.6% of zileuton adverse event reports involve female patients and 24.3% involve male patients. The largest age group is adult at 74%. These figures reflect who reports side effects, not underlying risk.

Sex

Female63.6%
Male24.3%
Unknown12.0%

Age group

< 20.0%
2–110.0%
12–171.1%
18–6473.7%
65+25.2%

What is zileuton used for

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

Anaphylactic ReactionAnaphylactic ShockAspirin-exacerbated Respiratory DiseaseAsthmaAnaphylaxis ProphylaxisAsthmaAsthma ProphylaxisBlood Immunoglobulin EBronchial DysplasiaBronchial HyperreactivityChronic Eosinophilic RhinosinusitisChronic Myeloid LeukaemiaChronic Obstructive Pulmonary DiseaseChronic SinusitisCondition Aggravated

Showing 15 of 61 indications

Zileuton brand names and reporting trend

Zileuton is sold under the brand name Zyflo Cr.

Brand names

Zyflo Cr200

Quarterly reports (20042025)

20052010201520202025

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

Taking zileuton with another medication?

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