Pediair Mechanism of Action

Pharmacotherapeutic group: Leukotriene receptor antagonists. ATC-code: R03D C03.
Pharmacology: Pharmacodynamics: Mechanism of action: The cysteinyl leukotrienes (LTC4, LTD4, LTE4) are potent inflammatory eicosanoids released from various cells including mast cells and eosinophils. These important pro-asthmatic mediators bind to cysteinyl leukotriene receptors (CysLT) found in the human airway and cause airway actions, including bronchoconstriction, mucous secretion, vascular permeability, and eosinophil recruitment.
Pharmacodynamic effects: Montelukast is an orally active compound, which binds with high affinity and selectivity to the CysLT1 receptor.
Pharmacokinetics: Absorption: Montelukast is rapidly and nearly completely absorbed following oral administration. The mean oral bioavailability is 64%. The oral bioavailability and Cmax are not influenced by a standard meal.
Distribution: Montelukast is more than 99% bound to plasma proteins. The steady-state volume of distribution of montelukast averages 8 to 11 liters.
Metabolism: Montelukast is extensively metabolized in the liver by cytochrome P450 isoenzymes CYP3A4 and CYP2C9. Therapeutic plasma concentrations of montelukast do not inhibit cytochromes P450 3A4, 2C9, 1A2, 2A6, 2C19, or 2D6.
Elimination: Montelukast and its metabolites are excreted principally in the faeces via the bile. Elimination Half-life: 2.7 to 5 hours.