It is an angiotensin II receptor blocker (ARB) that works by relaxing blood vessels. It is a calcium channel blocker that improves blood flow. Hydrochlorothiazide is a diuretic that helps to eliminate excess water and salt from the body, which can also help to lower blood pressure.This medications work to lower blood pressure by reducing the resistance in the blood vessels and decreasing the amount of fluid in the body. This combination may be particularly useful for people with moderate to severe hypertension who have not responded adequately to other treatments.It is important to take this medication as directed by a healthcare professional and to monitor blood pressure regularly to ensure that it remains within a healthy range. Additionally, it is important to report any side effects or concerns to a healthcare professional.