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Pharmacy and Medications

ACE+ARB combination

08/22/2005

Question:

My brother aged 65 years hypertensive is taking Ramipril+losartan ( 10+100) Atenolo+Alodipine ( 100+50). What is the reason for combination of Losartan+ramipril Is this not over;lapping since normally doctors use either of ACE or ARB ? What is the reason for ACE=ARB combination ?

Answer:

Ramipril is an angiotensin converting enzyme inhibitor, or ACE inhibitor, which is used to treat hypertension and heart failure and reduce the risk of heart attack or stroke in patients who are at risk for such events. Ramipril works by inhibiting the production of a chemical called angiotensin II in the body. This chemical normally causes blood vessels to constrict and blood pressure to increase. By reducing the production of this chemical, ramipril causes blood vessels to relax, which lowers blood pressure.

Losartan is an angiotensin II receptor blocker, or ARB, which is also used to treat hypertension and heart failure and reduce the risk of heart attack and stroke. In contrast, losartan works by blocking the action of the same chemical (angiotensin II) in the body that causes blood vessels to constrict, causing an increase in blood pressure. By blocking this chemical, losartan causes blood vessels to relax, which lowers blood pressure.

Both drugs work by interfering with one of the systems in the body that regulates blood pressure. However, ACE inhibitors and ARBs work by blocking the effects of a chemical in the body using two different mechanisms. As a result, it is thought that the combination of both drugs is likely to produce greater reductions in blood pressure than either agent alone. Several studies have shown the combination to provide some additional benefit in lowering blood pressure. However, the benefit is not always as great as expected and not every patient will benefit from combination therapy. Other studies have produced conflicting evidence on combination therapy; therefore, it is generally recommended that the maximum dose of one agent be used first before adding additional therapy with the other agent. Several ongoing studies are evaluating the benefits of combination therapy with ACE inhibitors and ARBs. These studies may help clarify the role of combined use of ACE inhibitors and ARBs.

The maximum recommended dose of ramipril and losartan is 20mg/day and 100mg/day, respectively. Your brother is currently taking the recommended maximum daily dose of losartan and a fairly high daily dose of ramipril. In addition, he is taking two other medications that affect blood pressure, atenolol and amlodipine, suggesting that his blood pressure may be difficult to control. For these reasons, his physician may feel that it necessary for him to be on both ramipril and losartan. Any concerns with medication therapy should be discussed with your physician, who can convey his reasons for prescribing such therapy and address your concerns personally.

This response was prepared by Lauren Barton, a PharmD candidate at the University of Cincinnati College of Pharmacy

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Response by:

Robert James Goetz, PharmD, DABAT
Assistant Professor of Pharmacy Practice
College of Medicine
University of Cincinnati