Salbutamol marketed as Albuterol, Ventolin, Aerolin, Ventorlin, Asthalin, Proventil, ProAir.

Salbutamol belong to a group of medications called bronchodilators. This medication relaxes the smooth muscle in the lungs and opens airways to improve breathing.

Each capsule contains 100 mg of guaifenesin and 2 mg of salbutamol. The combination of salbutamol and guaifenesin is to relieve respiratory obstruction and improve pulmonary ventilation.

Terbutaline marketed as Brethine, Bricanyl, Brethaire.

Terbutaline produces bronchodilation by stimulation of the B2 adrenergic receptors in bronchial smooth muscle, thereby causing relaxation of muscle fibres. This action is manifested by an increase in pulmonary function as demonstrated by FEV1 measurements. Terbutaline also produces a decrease in airway and pulmonary resistance.

Theophylline marketed as Dimethylxanthine.

Theophylline is a derivative of xanthine which works by relaxing the smooth muscle in the air passages of the lungs thereby making the tubes wider and breathing easier.