NOVALET-H TAB. Losartan+Hydrochlorothiazide is used in the treatment of Hypertension (high blood pressure). combination of two medicines: Losartan and Hydrochlorothiazide, which lowers the blood pressure effectively. Losartan is an angiotensin receptor blocker (ARB). It works by blocking the hormone angiotensin thereby relaxing blood vessels. This allows the blood to flow more smoothly and the heart to pump more efficiently. Hydrochlorothiazide is a diuretic that removes extra water and certain electrolytes from the body.Over time it also relaxes blood vessels and improves blood flow.