Natrilix SR 1.5mg 30 Tabs - indapamide Generic name: indapamide How does it work? Natrilix SR tablets contain the active ingredient indapamide, which is a type of medicine called a diuretic. (NB. Indapamide is also available without a brand name, ie as the generic medicine.) Diuretics work by causing the kidneys to increase the amount of salts such as potassium and sodium that are filtered out of the blood and into the urine. When these salts are filtered out of the blood by the kidneys, water is also drawn alongside. As diuretics increase the removal of salts from the blood, they also cause more water to be drawn out of the blood and into the urine. Removing water from the blood decreases the volume of fluid circulating through the blood vessels. This subsequently decreases the pressure within the blood vessels. Diuretics are therefore used to lower high blood pressure. Although indapamide is classed as a diuretic, its main mechanism of lowering blood pressure is due to a direct action on the blood vessels. Indapamide causes the blood vessels to widen, which reduces the pressure inside the blood vessels. This helps to lower blood pressure. Natrilix SR tablets are prolonged-release tablets. They are designed to release the indapamide slowly over several hours, thus producing a steady blood level of the medicine throughout the day. The tablets must be swallowed whole with water and not be broken, crushed or chewed, as this would damage the prolonged-release action. What is it used for? * High blood pressure with no known cause (essential hypertension).