What is it?

Irbesartan Winthrop is a medicine that contains the active substance irbesartan. It is available as white, oval tablets (75, 150 and 300 mg).
This medicine is the same as Aprovel, which is already authorised in the European Union (EU). The company that makes Aprovel has agreed that its scientific data can be used for Irbesartan Winthrop.

Table of Contents
What is it used for?
How is it used?
How does it work?
How has it been studied?
What benefits has it shown during the studies?
What is the risk associated?
Why has it been approved?

What is it used for?

Irbesartan Winthrop is used in patients who have essential hypertension (high blood pressure). ?Essential? means that the hypertension has no obvious cause. Irbesartan Winthrop is also used to treat kidney disease in patients with hypertension and type 2 diabetes (non-insulin-dependent diabetes). Irbesartan Winthrop is not recommended for use in patients below 18 years of age, because of a lack of information on safety and effectiveness in this age group.
The medicine can only be obtained with a prescription.

How is it used?

Irbesartan Winthrop is taken by mouth, with or without food. The usual recommended dose is 150 mg once a day. If the blood pressure is not sufficiently controlled, the dose can be increased to 300 mg a day or other medicines for hypertension can be added, such as hydrochlorothiazide. A starting dose of 75 mg can be used in patients receiving haemodialysis (a blood clearance technique) or in patients over 75 years of age.
In patients with hypertension and type 2 diabetes, Irbesartan Winthrop is added to other treatments for hypertension. Treatment is started at 150 mg once a day and is usually increased to 300 mg once a day.

How does it work?

The active substance in Irbesartan Winthrop, irbesartan, is an ?angiotensin II receptor antagonist?, which means that it blocks the action of a hormone in the body called angiotensin II. Angiotensin II is a powerful vasoconstrictor (a substance that narrows blood vessels). By blocking the receptors to which angiotensin II normally attaches, irbesartan stops the hormone having an effect, allowing the blood vessels to widen. This allows the blood pressure to drop, reducing the risks associated with high blood pressure, such as having a stroke.

How has it been studied?

Irbesartan Winthrop was originally studied in 11 trials for its effects on blood pressure. Irbesartan Winthrop was compared with placebo (a dummy treatment) in 712 patients and with other medicines for hypertension (atenolol, enalapril or amlodipine) in 823 patients. Its use in combination with hydrochlorothiazide was also examined in 1,736 patients. The main measure of effectiveness was the reduction in diastolic blood pressure (the blood pressure measured between two heartbeats). For the treatment of kidney disease, Irbesartan Winthrop was studied in two large studies involving a total of 2,326 patients with type 2 diabetes. Irbesartan Winthrop was used for two years or more. One study looked at markers of kidney damage by measuring whether the kidneys were releasing the protein albumin into the urine. The second study looked at whether Irbesartan Winthrop increased the time taken until the patients? blood creatinine levels had doubled (a marker of kidney disease), until they needed a kidney transplant or dialysis, or until they died. In this study, Irbesartan Winthrop was compared with placebo and with amlodipine.

What benefits has it shown during the studies?

In the blood pressure studies, Irbesartan Winthrop was more effective than placebo at reducing diastolic blood pressure and had similar effects to the other medicines for hypertension. When used with hydrochlorothiazide, the effects of the two medicines were additive.
In the first kidney disease study, Irbesartan Winthrop was more effective than placebo at reducing the risk of developing kidney damage as measured by protein excretion. In the second kidney disease study, Irbesartan Winthrop reduced the relative risk of a doubling of blood creatinine levels, needing a kidney transplant or dialysis, or death during the study by 20% in comparison with placebo. There was a 23% relative risk reduction compared with amlodipine. The main benefit was on the effect on blood creatinine levels.

What is the risk associated?

The most common side effects with Irbesartan Winthrop (seen between 1 and 10 patients in a 100) are dizziness, nausea (feeling sick) or vomiting, fatigue (tiredness) and increases in blood creatine kinase levels (an enzyme found in muscles). In addition, more than 1 patient in 100 with type 2 diabetes and kidney disease has the following side effects: hyperkalaemia (high blood potassium levels), orthostatic dizziness (dizziness when standing up), orthostatic hypotension (low blood pressure when standing up) and musculoskeletal (joint) pain. For the full description of all side effects reported with Irbesartan Winthrop, see the Package Leaflet.
Irbesartan Winthrop should not be used in people who may be hypersensitive (allergic) to irbesartan or any of the other ingredients. It must not be used in women who are more than three months pregnant. Its use during the first three months of pregnancy is not recommended.

Why has it been approved?

The Committee for Medicinal Products for Human Use (CHMP) decided that Irbesartan Winthrop?s benefits are greater than its risks for the treatment of hypertension and of renal disease in patients with hypertension and type 2 diabetes mellitus. The Committee recommended that Irbesartan Winthrop be given marketing authorisation.

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