Zafirlukast

Breast Feeding; Lactation; Milk, Human; Anti-Asthmatic Agents; Leukotriene Antagonists

FDA approved drugs -> Active ingredient

FDA approved drugs -> Active ingredient

H413 (92.9%): May cause long lasting harmful effects to aquatic life [Hazardous to the aquatic environment, long-term hazard]

P273, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 42 reports by companies from 2 notifications to the ECHA C&L Inventory.

Prospective studies have shown that ALT elevations occur in 1.5% of patients receiving zafirlukast, most of which are mild, asymptomatic and self limited even with continuing therapy. A similar rate of transient ALT elevations is often found in placebo recipients. Clinically apparent liver disease from zafirlukast is rare, but many convincing cases have been reported, several of which were severe and resulted in hepatic failure, need for liver transplantation or death. The onset of symptoms of liver injury is typically within 2 to 6 months of starting therapy, but cases with longer latency periods have been reported (8-13 months). Symptoms include fatigue, nausea, and right upper quadrant pain followed by dark urine, jaundice and pruritus. The pattern of liver enzyme elevation is usually hepatocellular and resembles acute viral hepatitis. Eosinophilia is common but immunoallergic features are usually not prominent and autoantibodies are uncommon (eosinophilia may be due to the underlying allergic asthmatic condition). Fatal cases have been described. Reexposure can lead to more rapid and severe reappearance of injury and should be avoided. Zafirlukast can also cause systemic vasculitis and eosinophilia (Churg-Strauss Syndrome) which may be accompanied by hepatic involvement and mild enzyme elevations.

R - Respiratory system

QR - Respiratory system

Zafirlukast is a synthetic, selective peptide leukotriene receptor antagonist (LTRA) indicated for the prophylaxis and chronic treatment of asthma. Patients with asthma were found in one study to be 25-100 times more sensitive to the bronchoconstricting activity of inhaled LTD₄ than nonasthmatic subjects. <i>In vitro</i> studies demonstrated that zafirlukast antagonized the contractile activity of three leukotrienes (LTC₄, LTD₄ and LTE₄) in conducting airway smooth muscle from laboratory animals and humans. Zafirlukast prevented intradermal LTD₄-induced increases in cutaneous vascular permeability and inhibited inhaled LTD₄-induced influx of eosinophils into animal lungs.

Zafirlukast is a selective and competitive receptor antagonist of leukotriene D4 and E4 (LTD₄ and LTE4), components of slow-reacting substance of anaphylaxis (SRSA). Cysteinyl leukotriene production and receptor occupation have been correlated with the pathophysiology of asthma, including airway edema, smooth muscle constriction, and altered cellular activity associated with the inflammatory process, which contribute to the signs and symptoms of asthma.

Hepatic

Zafirlukast has known human metabolites that include 3-hydroxycyclopentyl N-[3-({2-methoxy-4-[(2-methylbenzenesulfonyl)carbamoyl]phenyl}methyl)-1-methylindol-5-yl]carbamate and cyclopentyl N-[1-(hydroxymethyl)-3-({2-methoxy-4-[(2-methylbenzenesulfonyl)carbamoyl]phenyl}methyl)indol-5-yl]carbamate.

XZ629S5L50

ZAFIRLUKAST