Ambroxol Terbutaline Guaiphenesin Menthol Syrup
Mechanism of Action of Terbutaline
Terbutaline is a ?2 receptor agonist. Terbutaline directly relaxes the airway smooth muscles and produces bronchodilation. Stimulation of ?2 receptors activates Gs adenylyl-cyclase -cyclic AMP path way and produces reduction in smooth muscle tone. ?2 receptor agonists also increases the conductance of large Ca2+sensitive K+ channels in airway smooth muscles and leads to membrane hyperpolarisation and relaxation of smooth muscles.
Tocolytic action: In premature labour Terbutaline relaxes uterine smooth muscles and inhibits uterine contractions.
Mechanism of Action of Guaiphenesin
Guaiphenesin is an expectorant which after absorption from the gastrointestinal tract secreted by tracheobronchial glands and directly increase bronchial secretion and mucosal ciliary action. It increases respiratory tract fluid by reducing adhesiveness and surface tension, reducing viscosity of the secretions and there by facilitating their removal and clears chest congestion.
Mechanism of Action of Ambroxol
Ambroxol hydrochloride acts as an expectoration improver and mucolytic agent. It decreases mucus viscosity by altering its structure. It depolymerises mucopolysaccharides directly as well as by liberating lysosomal enzymes and by breaking network of fibres in tenacious sputum . It induces thin copious bronchial secretion and possesses antioxidant properties.