Natrixam is prescribed as substitution treatment of high blood pressure in patients already taking indapamide and amlodipine from separate tablets in the same strength. Natrixam is a combination of two active ingredients, indapamide and amlodipine. Indapamide is a diuretic. Diuretics increase the amount of urine produce by the kidneys. However, indapamide is different from other diuretics, as it only causes a slight increase in the amount of urine produced. Amlodipine is a calcium antagonist and it works by relaxing blood vessels, so that blood passes through them more easily. Each of the active ingredients reduces blood pressure.