Zafirlukast

A to Z Drug Facts

  Action Inhibits 3 leukotriene receptor types. Leukotrienes have been associated with the longer, inflammatory component of asthma.

  Indications Prophylaxis and chronic treatment of asthma in adults and children older than 5 yr.

  Contraindications Standard considerations.

  Route/Dosage

Adults and Children 12 yr or older: PO 20 mg bid. Children 5 to 11 yr: PO 10 mg bid.

  Interactions

Aspirin: Increased zafirlukast plasma levels. Erythromycin, theophylline: Lowered zafirlukast plasma concentrations. Warfarin: Zafirlukast potentiates the hypoprothrombinemic effect of warfarin. Significant increase in the prothrombin time (PT) may result.

  Lab Test Interferences None well documented.

  Adverse Reactions

CNS: Headache; dizziness. GI: Nausea; diarrhea; dyspepsia; abdominal pain; vomiting. HEPATIC: Elevation in transaminase levels. OTHER: Infection; fever; asthenia; generalized pain; myalgia; back pain.

  Precautions

Pregnancy: Category B. Lactation: Excreted in breast milk. Children: Safety and efficacy in children younger than 5 yr of age not established. Elderly: Drug clearance increase with age. Acute asthma: Zafirlukast is not effective in treating acute asthmatic symptoms, but it can be continued during these times. Infections: Elderly patients experienced an increased frequency of infections (primarily respiratory) compared to placebo-treated patients. These appeared to be associated with coadministration of inhaled corticosteroids.

  Administration/Storage

• Administer at least 1 hr before or 2 hr after meals.
• Store at room temperature. Protect from light and moisture in tightly closed container.
• Do not administer to reverse acute asthma attacks.
• Administer with caution in elderly and patients with liver disease.

  Assessment/Interventions

• Obtain patient history, including drug history, and any known allergies.
• Monitor patients on warfarin, aspirin, and other similar anticoagulants for signs of bleeding.
• Assess patients respiratory status prior to and during therapy.
• Ensure that LFTs are monitored during therapy.
• Assess for potential infections in elderly patients older than 55 yr especially when coadministered with corticosteroids.
• Monitor patient for medication effectiveness and side effects during therapy.
• Ensure that PTs are monitored in patients receiving warfarin and zafirlukast.

 Patient/Family Education

• Instruct patient to take zafirlukast at least 1 hr before or 2 hr after meals.
• Instruct patient to take medication as directed. Do not decrease dose or discontinue use even when symptom-free without consulting primary health care provider.
• Instruct patient not to decrease the dose or stop taking any anti-asthma medications unless instructed by health care provider.
• Educate patient in correct use of zafirlukast in relationship to other asthma medications. Be sure patient understands what to do in emergency situations and that zafirlukast is used to help prevent such events and NOT for treatment. However, advise patient to continue taking the zafirlukast during asthma exacerbations.
• Instruct patients on oral warfarin anticoagulant therapy to have their PTs monitored closely and watch for signs and symptoms of bleeding.
• Instruct female patients to notify primary health care provider if they are pregnant or plan to become pregnant.
• Advise patients not to breastfeed while taking this medication.
• Instruct patient not to take otc medications without consulting health care provider.

Books@Ovid
Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts