Asthma/COPD:

Indications for: ACCOLATE

Prophylaxis and chronic treatment of asthma.

Clinical Trials:

Three US double-blind, randomized, placebo-controlled, 13-week clinical trials in 1380 adults and children ≥12 years of age with mild to moderate asthma demonstrated that zafirlukast improved daytime asthma symptoms, nighttime awakenings, mornings with asthma symptoms, rescue beta2-agonist use, FEV1, and morning peak expiratory flow rate. 

  • Patient demographics

    • had a mean baseline FEV1 of approximately 75% of predicted normal

    • mean baseline beta2-agonist requirement of approximately 4-5 puffs of albuterol per day.

The results of the largest of the trials are shown below. 

Mean Change from Baseline at Study End Point:

Daytime Asthma symptom score (0-3 scale) 

  • Zafirlukast 20 mg twice daily (N=514) = -0.44*
  • Placebo = -0.25

Nightime Awakenings (number per week)

  • Zafirlukast 20 mg twice daily (N=514) = -1.27*
  • Placebo = -0.43

Mornings with Asthma Symptoms (days per week) 

  • Zafirlukast 20 mg twice daily (N=514) = -1.32*
  • Placebo = -0.75

Rescue β2 -agonist use (puffs per day)

  • Zafirlukast 20 mg twice daily (N=514) = -1.15*
  • Placebo = -0.24

FEV1 (L) 

  • Zafirlukast 20 mg twice daily (N=514) = +0.15*
  • Placebo = +0.05

Morning PEFR (L/min) 

  • Zafirlukast 20 mg twice daily (N=514) = +22.06*
  • Placebo = +7.63

Evening PEFR (L/min) 

  • Zafirlukast 20 mg twice daily (N=514) = +13.12*
  • Placebo = +10.14

* P <0.05, compared to placebo

In a second and smaller study, the effect of zafirlukast on most efficacy parameters was comparable to the active control (inhaled cromolyn sodium 1600 mcg four times per day) and superior to placebo at end point for decreasing rescue beta2-agonist use.

In these trials, improvement in asthma symptoms occurred within one week of initiating treatment with zafirlukast. The role of zafirlukast in the management of patients with more severe asthma, patients receiving antiasthma therapy other than as-needed, inhaled beta2-agonists, or as an oral or inhaled corticosteroid-sparing agent remains to be fully characterized.

Adults and Children:

<5yrs: not established. Take 1hr before or 2hrs after meals. 5–11yrs: 10mg twice daily. ≥12yrs: 20mg twice daily.

ACCOLATE Contraindications:

Hepatic impairment including hepatic cirrhosis. 

ACCOLATE Warnings/Precautions:

Not for primary treatment of acute attack. Discontinue if clinical symptoms of liver dysfunction occur; do not resume if confirmed by lab results. Caution when withdrawing from oral steroids. Elderly. Pregnancy (Cat.B). Nursing mothers: not recommended.

ACCOLATE Classification:

Leukotriene receptor antagonist.

ACCOLATE Interactions:

Potentiates warfarin (monitor PT and adjust warfarin dose). Caution with drugs metabolized by CYP2C9 (eg, tolbutamide, phenytoin, carbamazepine) or CYP3A4 (eg, dihydropyridine calcium channel blockers, cyclosporine, cisapride). Zafirlukast plasma levels reduced by erythromycin, theophylline. Zafirlukast plasma levels increased by aspirin. May increase theophylline levels.

Adverse Reactions:

Headache, infection, GI upset, pain, fever; neuropsychiatric events (eg, insomnia, depression); rarely, hepatic dysfunction (esp. in females), agranulocytosis.

Metabolism:

Zafirlukast is extensively metabolized. The most common metabolic products are hydroxylated metabolites which are excreted in the feces.

In vitro studies using human liver microsomes showed that the hydroxylated metabolites of zafirlukast excreted in the feces are formed through the CYP2C9 pathway. Additional in vitro studies utilizing human liver microsomes show that zafirlukast inhibits the CYP3A4 and CYP2C9 isoenzymes at concentrations close to the clinically achieved total plasma concentrations.

Drug Elimination:

Following oral administration of radiolabeled zafirlukast, urinary excretion accounts for ~10% of the dose and the remainder is excreted in feces.

The mean terminal half-life of zafirlukast is ~10 hours in both normal adult patients and patients with asthma. 

Generic Drug Availability:

YES

How Supplied:

Tabs—60