Deriphyllin S PR Tablet is a bronchodilator medication used to treat symptoms of asthma and chronic obstructive pulmonary disease (COPD). It contains Etofylline, Salbutamol, and Theophylline, which work by relaxing and widening the blocked airways, making breathing easier. In some cases, it may cause side effects such as nausea, vomiting, stomach upset, headache, dizziness, tremors (shaking), restlessness, irritability, sweating, muscle cramps, and insomnia (lack of sleep). Before taking this medicine, inform your doctor if you are allergic to any of its ingredients, if you are pregnant or breastfeeding, and about all the medications you are taking and any pre-existing medical conditions.