Olmezest 20 Tablet does not have a diuretic. Olmezest 20 Tablet is a medicine used to lower high blood pressure. It belongs to a group of medicines called angiotensin receptor blocker (ARB). These medicines lower blood pressure by relaxing the blood vessels. When prescribed by a doctor, Olmezest 20 Tablet can also be combined with a diuretic for providing additional benefit in the reduction of blood pressure.