Dosing & Uses
Dosage Forms & Strengths
tablet
- 600mg
tablet, extended release
- 600mg
Asthma
Extended release: 1200 mg PO twice daily, within 1 hour after morning and evening meals
Conventional: 600 mg PO four times daily
Monitor: LFTs
Contraindicated in hepatic dysfunction
Dosage Forms & Strengths
tablet
- 600mg
tablet, extended release
- 600mg
Asthma
<12 years
- Safety and efficacy not established
- The FDA has not required pediatric studies in patients <12 years old due to the risk of hepatotoxicity; not recommeded for children younger than 12 years
>12 years
- Extended Release: 1200 mg PO twice daily, within 1 hour after morning and evening meals
- Conventional: 600 mg PO four times daily
- Monitor: LFTs
- Contraindicated in hepatic dysfunction
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Adverse Effects
>10%
Headache (24.6%)
1-10%
Abdominal pain (5%)
ALT elevation ≥3 times ULN (1.9-5%)
Asthenia (3.8%)
Dyspepsia (8.2%)
Diarrhea (5%)
Generalized pain (7.8%)
Nausea (5.5%)
Leukopenia (1-3%)
Myalgia (7%)
Weakness (4%)
Sinusitis (7%)
Pharyngolaryngeal pain (5%)
< 1%
Hepatitis
Behavioral changes
Jaundice
Liver failure
Suicidality
Suicide
Warnings
Contraindications
Hypersensitivity
Liver disease, LFT's ≥3x ULN
Cautions
Not indicated for use in acute bronchospasm
History of liver disease, heavy alcohol use
Behavioral changes and sleep disorders reported
Not recommended for patients <12 years due to risk of hepatotoxicity
Pregnancy & Lactation
Pregnancy
There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to asthma medications during pregnancy; for more information, contact the MothersToBaby Pregnancy Studies conducted by Organization of Teratology Information Specialists at 1- 877-311-8972 or visit http://mothertobaby.org/pregnancy-studies
There are no adequate human data on use in pregnant women to inform a drug associated risk
Animal data
- In animal studies, oral administration to pregnant rats and rabbits during organogenesis produced adverse developmental outcomes; structural abnormalities (cleft palate) were observed in rabbits at a dose similar to maximum recommended human daily oral dose (MRHD), alterations to growth (reduced fetal body weight and increased skeletal variations) were observed in rats at maternal plasma exposures 20 times greater than at MRHD; in a pre- and post-natal development study, oral administration to pregnant rats from organogenesis through weaning at maternal plasma exposures 20 times greater than MRHD resulted in reduced pup survival and body weights; the drug and/or its metabolites cross placental barrier of rats; therefore, drug may be transmitted from mother to developing fetus
Lactation
The drug and metabolites are excreted in rat milk; it is not known if zileuton is excreted in human milk, nor are there data on effects of drug on breastfed infant or effects on maternal milk production; because many drugs are excreted in human milk, and because of potential for tumorigenicity shown in animal studies, the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for drug and any potential adverse effects on breastfed child from drug or from the underlying maternal condition
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Inhibitor of 5-lipoxygenase, which inhibits formation of LTB4, LTC4, LTD4, & LTE4
Inhibition of leukotriene formation reduces eosinophil and neutrophil migration, neutrophil and monocyte aggregation, capillary permeability, and smooth muscle contraction
Pharmacokinetics
Half-Life: 2.5 hr
Onset: 2-5 hr
Peak Plasma Time: 1.7 hr
Protein Bound: 93%
Vd: 1.2 L/kg
Metabolites: O-glucuronide conjugate & N-dehydroxylated metabolite
Clearance: 7 mL/min/kg
Excretion: Urine (95%); feces (2%)
Enzymes inhibited: hepatic CYP1A2, CYP3A4, and CYP2C9
Images
Patient Handout
Formulary
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Adding plans allows you to:
- View the formulary and any restrictions for each plan.
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- Compare formulary status to other drugs in the same class.
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