Isoprenaline sulphate is primarily used in the treatment of bradycardia, a condition characterized by an abnormally slow heart rate. It acts as a beta-adrenergic agonist, stimulating the heart to beat faster and with greater force, thereby improving cardiac output. Additionally, it is employed in managing certain types of heart block and as an emergency treatment for cardiac arrest in some cases. Beyond cardiovascular applications, it is also utilized in bronchial asthma and chronic obstructive pulmonary disease (COPD) to relax the smooth muscles of the airways, facilitating easier breathing. In clinical settings, it is sometimes used to assess bronchial hyperresponsiveness in diagnostic tests.