Hydralazine is a medication primarily used to treat high blood pressure, also known as hypertension. It works by relaxing the blood vessels, allowing blood to flow more easily, which helps to lower blood pressure. Hydralazine is often prescribed when other medications are not effective or suitable for a patient. This drug is typically taken orally in tablet form, but it can also be administered intravenously in a hospital setting. Common side effects may include headaches, dizziness, and rapid heartbeat. Patients should follow their doctor's instructions carefully to ensure safe and effective use of hydralazine.