Health Centres - Cozaar (losartan)
How does it work?
Cozaar tablets contain the active ingredient losartan potassium, which is a type of medicine called an angiotensin II antagonist. It works by preventing the action of a hormone in the body called angiotensin II.
Angiotensin II normally acts on special receptors in the body, with two main results. Firstly, it causes the peripheral blood vessels to narrow, and secondly, it stimulates the production of another hormone called aldosterone. Aldosterone causes salt and water to be retained by the kidneys, which increases the volume of fluid in the blood vessels.
Losartan blocks the receptors that angiotensin II acts on, and so prevents its actions. The main result of this is that the peripheral blood vessels are allowed to widen, which means that there is more space and less resistance in these blood vessels. This is the main mechanism by which the pressure in the blood vessels is lowered.
Blocking the actions of angiotensin II also reduces the action of aldosterone on the kidneys. The result of this is an increase in the amount of fluid removed from the blood by the kidneys. This decreases the amount of fluid in the blood vessels, which also lessens the resistance and pressure in the blood vessels.
The combined overall effect of these changes is to lower the blood pressure, hence losartan is used to treat high blood pressure.
Losartan has been shown to reduce the risk of stroke in people who have high blood pressure together with an enlargement in the left side of their heart (left ventricular hypertrophy). People with both these conditions may therefore be prescribed losartan to reduce their chances of experiencing a stroke. However, this medicine is not effective for this particular use in black patients.
Losartan has also been shown to delay the progression of kidney disease in people with type 2 diabetes who have related kidney complications. If you have diabetic kidney disease you may be prescribed losartan for this reason, regardless of whether or not you also have high blood pressure.
What is it used for?
-
High blood pressure
- Reducing risk of stroke in people with high blood pressure and an enlarged heart (left ventricular hypertrophy)
- Delaying progression of kidney disease in people with type 2 diabetes and kidney complications (diabetic nephropathy/macroalbuminuria).
Warning!
- Dizziness and weariness may occasionally occur during treatment with blood pressure lowering medicines. This may be made worse by drinking alcohol. If you are affected, caution is required when driving or operating machinery.
- You should have regular blood tests to monitor the amount of potassium in your blood while you are taking this medicine, particularly if you are elderly or have any problems with your kidneys.
Use with caution in
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