montelukast

General

Pronunciation
mon-te-LOO-kast [Pronunciation]

Trade Name(s)

• Singulair

Pregnancy Category
Category B

Ther. class.
allergy, cold and cough remedies
bronchodilators

Pharm. class.
leukotriene antagonists

Indications

• Prevention and chronic treatment of asthma.

• Management of seasonal allergic rhinitis.

• Prevention of exercise-induced bronchoconstriction in patients 15 yr and older.

Action

• Antagonizes the effects of leukotrienes, which mediate the following:

» Airway edema,

» Smooth muscle constriction,

» Altered cellular activity.

• Result is decreased inflammatory process, which is part of asthma and allergic rhinitis.

Therapeutic Effect(s):

• Decreased frequency and severity of acute asthma attacks.

• Decreased severity of allergic rhinitis.

• Decreased attacks of exercise-induced bronchoconstriction.

Pharmacokinetics

Absorption: Rapidly absorbed (63–73%) following oral administration.

Distribution: Unknown.

Protein Binding: 99%.

Metabolism and Excretion: Mostly metabolized by the liver (by P450 3A4 and 2C9 enzyme systems); metabolites eliminated in feces via bile; negligible renal excretion.

Half-life: 2.7–5.5 hr.

TIME/ACTION PROFILE (improved symptoms of asthma)

ROUTE	ONSET	PEAK†	DURATION
PO (swallow)	within 24 hr	3–4 hr	24 hr
PO (chew)	within 24 hr	2–2.5 hr	24 hr

†Blood levels

Contraindication/Precautions

Contraindicated in:
Hypersensitivity.

Use Cautiously in:

• Acute attacks of asthma;

• Phenylketonuria (chewable tablets contain aspartame);

• Hepatic impairment (may need ↓ doses);

• Reduction of corticosteroid therapy (may ↑ the risk of eosinophilic conditions);

• OB: Lactation: Pedi: Pregnancy, lactation, or children <1 yr (safety not established).

Adverse Reactions/Side Effects

CNS: SUICIDAL THOUGHTS, agitation, aggression, anxiety, depression, disorientation, dream abnormalities, fatigue, hallucinations, headache, insomnia, irritability, restlessness, tremor, weakness.

EENT: nosebleed, otitis (children), sinusitis (children).

Resp: cough, rhinorrhea.

GI: abdominal pain, diarrhea (children), dyspepsia, nausea (children), ↑ liver enzymes.

Neuro: tremor.

Derm: rash.

Misc: EOSINOPHILIC CONDITIONS (INCLUDING CHURG-STRAUSS SYNDROME) , fever.

*CAPITALS indicates life-threatening.
*italic indicates most frequent.

Interactions

Drug-Drug
Drugs which induce the CYP450 enzyme system ( phenobarbital and rifampin ) may ↓ the effects of montelukast.

Route/Dosage

Asthma and Allergic Rhinitis

• PO (Adults and Children ≥14 yr): 10 mg once daily..

• PO (Children 6–14 yr): 5 mg once daily (as chewable tablet)..

• PO (Children 2–5 yr): 4 mg once daily (as chewable tablet or granules)..

• PO (Children 6–23 mo): 4 mg once daily (as oral granules)..

Exercise-Induced Bronchoconstriction (EIB)

• PO (Adults and Children ≥15 yrs): 10 mg at least 2 hr before exercise. Do not take within 24 hr of another dose; if taking daily doses, do not take dose for EIB..

Availability

• Tablets: 10 mg

» Cost: $466.95/90.

• Chewable tablets (cherry flavor): 4 mg, 5 mg

» Cost: 4 mg $466.48/90, 5 mg $463.96/90.

• Oral granules: 4 mg/packet

» Cost: $490.01/90.

Assessment

• Assess lung sounds and respiratory function prior to and periodically during therapy.

• Assess allergy symptoms (rhinitis, conjunctivitis, hives) before 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

• May cause ↑ AST and ALT concentrations.

Potential Nursing Diagnoses

• Ineffective airway clearance (Indications)

Implementation

• Do not confuse Singulair (montelukast) with Sinequan (doxepin).

• Doses of inhaled corticosteroids may be gradually decreased with supervision of health care professional; do not discontinue abruptly.

• PO: For asthma, administer once daily in the evening. For allergic rhinitis, may be administered at any time of day.

» Administer granules directly into mouth or mixed in a spoonful of cold or room temperature foods (use only applesauce, mashed carrots, rice, or ice cream). Do not open packet until ready to use. After opening packet, administer full dose within 15 min. Do not store mixture. Discard unused portion. Do not dissolve granules in fluid, but fluid may be taken following administration. Granules may be administered without regard to meals.

Patient/Family Teaching

• Instruct patient to take medication daily in the evening, even if not experiencing symptoms of asthma. 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.

• Advise patient that montelukast is not used to treat acute asthma attacks, but may be continued during an acute exacerbation. Patient should carry rapid-acting therapy for bronchospasm at all times. Advise patient to notify health care professional if more than the maximum number of short-acting bronchodilator treatments prescribed for a 24-hr period are needed.

• Encourage patient and family to be alert for emergence of anxiety, agitation, panic attacks, insomnia, irritability, hostility, impulsivity, akathisia, hypomania, mania, worsening of depression and suicidal ideation, especially during early antidepressant therapy. Assess symptoms on a day-to-day basis as changes may be abrupt. If these symptoms occur, notify health care professional.

Evaluation/Desired Outcomes

• Prevention of and reduction in symptoms of asthma.

• Decrease in severity of allergic rhinitis.

• Prevention of exercise-induced bronchoconstriction.