Terbutaline

Terbutaline is a type of sympathomimetic drug. Terbutaline is a selective β2 receptor agonist that is clinically used to treat asthma. Since terbutaline is an agonist selective to β2 receptors, it activates β2 receptors in smooth muscles and stimulates sympathetic responses, including the increased relaxation of smooth muscles. Relaxation of smooth muscles in bronchi and trachea provides the effect of airway widening and hence can be served as a bronchodilator for asthma treatment. As terbutaline is selective to β2 receptors, it has relatively less effect on the heart, preventing heart-related side effects. Side effects of terbutaline includes peripheral vasodilation, tremor due to stimulation of β2 receptors in skeletal muscle, and tachycardia due to slight effect on β1 receptors. Therefore, terbutaline is mostly administered through inhalation to produce localized effect on the lungs, hence reduces side effects. Terbutaline can also be used to prevent premature labour, through the relaxation of uterine smooth muscles.