Zafirlukast

Indications

Zafirlukast is used for: Chronic asthma

Adult Dose

Oral Chronic asthma Adult: 20 mg bid. Hepatic impairment: Contraindicated.

Child Dose

Oral Chronic asthma Child: 5-11 yr: 10 mg bid. >12 yr: 20 mg bid.

Renal Dose

Renal Impairment Dose adjustment not necessary

Administration

Should be taken on an empty stomach. Take at least 1 hr before or 2 hr after meals.

Contra Indications

Hypersensitivity, hepatic impairment, cirrhosis, acute asthmatic attacks. Lactation.

Precautions

Not indicated for use in the reversal of bronchospasm in acute asthma attacks. Avoid abrupt substitution to oral or inhaled corticosteroids. Renal impairment. Pregnancy and lactation. Monitoring Parameters Monitor for improvements in air flow; monitor closely for sign/symptoms of hepatic injury; periodic monitoring of LFTs. Lactation: Excreted in breast milk; not recommended

Pregnancy-Lactation

Pregnancy Category: B Lactation: Excreted in breast milk; not recommended

Interactions

May enhance anticoagulant activity of warfarin resulting to increased prothrombin time. Decreased plasma levels w/ theophylline, terfenadine and erythromycin. Increased plasma levels w/ fluconazole and high dose aspirin.

Adverse Effects

Side effects of Zafirlukast : >10% headache (12.9% in age >12 yr) 1-10% Abdominal pain (1.8%), Infection (3.5%), Nausea (3.1%), Diarrhea (2.8%), Generalized pain (1.8%), Vomiting (1.5%), Dyspepsia/gastritits (1.3%), Increased ALT (1.5%), Infection (4%), Back pain (2%), Weakness (2%), Myalgia (2%) Frequency Not Defined Eosinophilia Eosinophilic pneumonia Vasculitis Malaise Bleeding Bruising Potentially Fatal: Severe hepatotoxicity.

Mechanism of Action

Zafirlukast selectively antagonises the leukotriene D4 receptor. It inhibits bronchoconstriction caused by various inhaled antigens or irritants. It is not used in acute asthma attacks.