zileuton

Inhibits the enzyme 5-lipoxygenase that catalyzes to formation of leukotrienes. Leukotrienes are components of slow-reacting substance of anaphylaxis and mediate the following:
- Airway edema,
- Smooth muscle constriction,
- Altered cellular activity.
Result is decreased inflammatory process that is part of asthma.

Therapeutic effects:

Decreased incidence and severity of asthma episodes.

Pharmacokinetics ⬆ ⬇

Absorption: Rapidly absorbed following oral administration.

Distribution: Unknown.

Protein Binding: 93%.

Metabolism/Excretion: Mostly metabolized by the liver.

Half-Life: 2.5 hr.

Time/Action Profile ⬆ ⬇

(improvement in pulmonary function)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	1.7 hr	unknown

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Active liver disease or transaminases ≥3 times the upper limit of normal (ULN).

Use Cautiously in:

Acute attacks of asthma;
History of liver disease or alcohol consumption;
OB: Safety not established in pregnancy;
Lactation: Use while breastfeeding only if potential maternal benefit outweighs potential risk to infant;
Pedi: Children 12 yr (safety and effectiveness not established).

Adv. Reactions/Side Effects ⬆ ⬇

CV: chest pain

Derm: pruritus

EENT: conjunctivitis

GI: abdominal pain, constipation, dyspepsia, flatulence, ↑liver enzymes, nausea, vomiting

GU: urinary tract infection, vaginitis

MS: arthralgia, myalgia, neck pain

Neuro: headache, agitation, aggression, anxiety, depression, dizziness, dream abnormalities, hallucinations, hypertonia, insomnia, irritability, malaise, nervousness, restlessness, somnolence, SUICIDAL THOUGHTS, tremor, weakness

Misc: fever, lymphadenopathy

Interactions ⬆ ⬇

Drug-drug:

↑levels and effects of theophylline, beta blockers, propranolol, and warfarin.

Food slows but does not alter extent of absorption.

Route/Dosage ⬆ ⬇

PO (Adults and Children ≥12 yr): Immediate-release: 600 mg 4 times daily; Extended-release: 1200 mg twice daily.

Availability ⬆ ⬇

(Generic available)

Tablets: 600 mg
Extended-release tablet: 600 mg

Assessment ⬆ ⬇

Assess lung sounds and respiratory function prior to and periodically during therapy.
Monitor closely for changes in behavior that could indicate the emergence or worsening of depression or suicidal thoughts.

Lab Test Considerations:

Monitor ALT prior to therapy, monthly for the first 3 mo, every 2 mo for the 1st yr of therapy, and periodically thereafter. May cause ↑ ALT concentrations. If ALT ≥5 times the ULN or the patient is symptomatic, zileuton therapy should be discontinued.
- May occasionally cause transient low WBC.

Implementation ⬆ ⬇

PO: Administer extended-release tablets within 1 hr after morning and evening meals. DNC: Swallow extended-release tablets whole; do not crush, break, or chew.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take medication as directed, at evenly spaced intervals, even if not experiencing symptoms of asthma. If a dose of extended-release product is missed, omit and take next dose at scheduled time. Do not double doses. Do not discontinue therapy without consulting health care professional.
Instruct patient not to discontinue or reduce other asthma medications without consulting health care professional. Health care professional should be notified if more short-acting bronchodilators than usual or more than the maximum number for 24 hr of inhalations of short-acting bronchodilator are needed.
Advise patient that zileuton is not used to treat acute asthma attacks but may be continued during an acute exacerbation.
Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
Instruct patient to notify health care professional immediately if upper right quadrant pain, nausea, fatigue, lethargy, pruritus, jaundice, or flu-like symptoms occur.
Advise patient to notify health care professional of behavioral changes or thoughts of suicide.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if planning to breastfeed. Encourage patients who become pregnant during therapy to enroll in the pregnancy registry that monitors pregnancy outcomes in women exposed to asthma medications during pregnancy. For more information, contact the MothersToBaby Pregnancy Studies conducted by the Organization of Teratology Information Specialists at 1-877-311-8972 or visit http://mothertobaby.org/pregnancy-studies/.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇