Slozem XL is a brand name for a medication that contains diltiazem hydrochloride as its active ingredient. Diltiazem is a type of medicine known as a calcium channel blocker, which is used primarily in the treatment of hypertension (high blood pressure) and angina pectoris (chest pain caused by reduced blood flow to the heart). The "XL" in Slozem XL indicates that it is an extended-release formulation, designed to release the medication slowly over time to provide a more consistent therapeutic effect and potentially reduce the frequency of dosing compared to immediate-release formulations. By inhibiting the influx of calcium ions into cardiac and vascular smooth muscle during depolarization, diltiazem decreases myocardial contractility and dilates coronary and systemic arteries, thereby reducing blood pressure and improving blood flow to the heart.