Sodium nitroprusside is a medication primarily used to treat severe hypertension (high blood pressure) and heart failure. It works by relaxing blood vessels, allowing blood to flow more easily, which helps lower blood pressure quickly. This medication is usually administered intravenously in a hospital setting due to its potent effects. In addition to its use in emergencies, sodium nitroprusside can also be used during surgical procedures to control blood pressure. However, it must be monitored closely, as it can lead to side effects such as low blood pressure and cyanide toxicity if used for extended periods.