Fesobig 4 Tablet ER contains Fesoterodine Fumarate 4mg, an extended-release medication primarily used to treat overactive bladder symptoms such as urinary urgency, frequency, and urge incontinence. Fesoterodine belongs to the class of antimuscarinic agents, which work by blocking muscarinic receptors in the bladder's smooth muscle, thereby reducing involuntary contractions and increasing bladder capacity. This helps patients gain better control over their urinary habits and reduces episodes of leakage. The extended-release formulation ensures a steady release of the active ingredient over time, promoting consistent therapeutic effects and improving patient compliance by allowing once-daily dosing. Fesobig 4 Tablet ER is typically prescribed after a thorough evaluation by a healthcare professional and should be taken as directed, usually once daily with or without food. Common side effects may include dry mouth, headache, constipation, and blurred vision, but these are generally mild and transient. Patients with certain medical conditions such as urinary retention, gastric retention, uncontrolled narrow-angle glaucoma, or severe liver impairment should avoid this medication. It is important to inform the doctor about all existing health issues and medications to prevent potential interactions. Fesobig 4 Tablet ER offers an effective solution for managing overactive bladder symptoms, improving quality of life for many patients.