Dilzem SR is a brand name for the medication diltiazem, which is classified as a calcium channel blocker. It is primarily used in the management and treatment of hypertension (high blood pressure), angina pectoris (chest pain), and certain heart rhythm disorders. The "SR" in its name stands for "Sustained Release," indicating that the medication is formulated to release the active ingredient, diltiazem, slowly over time to provide a prolonged therapeutic effect. By inhibiting the influx of calcium ions into cardiac and vascular smooth muscle cells, Dilzem SR helps to relax the blood vessels, thereby reducing blood pressure and improving blood flow. This action not only helps in managing blood pressure but also reduces the workload on the heart, making it an effective option for patients with certain cardiovascular conditions.