Nuclin SR 250mg Tablet is a sustained-release medication primarily used to manage conditions like chronic obstructive pulmonary disease (COPD) and asthma. The active ingredient, Theophylline, works by relaxing the muscles in the airways, which helps to widen them and makes breathing easier. The "SR" (sustained-release) formulation ensures a prolonged effect, reducing the need for frequent dosing. This pack contains 100 tablets. Always follow the prescribed dosage and consult a healthcare provider for proper use.