Medications and Drugs
Angiotensin II Receptor Blockers (ARB)
Pharmacy Author:
Omudhome Ogbru, Pharm.D.
Medical Editor:
Jay W. Marks, M.D.
What
are angiotensin receptor blockers and how do they work?
Angiotensin
II is a very potent
chemical that causes the muscles surrounding the blood vessels to contract,
which thereby narrows the blood vessels. This narrowing increases the pressure
within the vessels and can cause high blood pressure (hypertension).
Angiotensin receptor blockers (ARBs) are medications that block the action of
angiotensin II. As a result, the blood vessels dilate and the blood pressure is
reduced. The lower blood pressure makes it easier for the heart to pump blood
and can improve heart failure. In addition, the progression of kidney disease
due to high blood pressure or diabetes is slowed.
For
what conditions are ARBs used?
ARBs
are used for controlling high blood pressure, treating heart failure, and
preventing kidney failure in people with diabetes or high blood pressure. Since
these medications have effects that are similar to those of ACE inhibitors, they
are often used when an ACE inhibitor can not be tolerated by patients.
Are
there any differences among the different types of ARBs?
ARBs
are similar in action and side effects. They differ in how they are eliminated
from the body and the extent to which they are distributed throughout the body.
Some ARBs need to be converted to an active form in the body before they
can lower blood pressure. In
addition, some ARBs are better at lowering blood pressure. In head to head
comparisons, irbesartan (AVAPRO) and candesartan (ATACAND) have demonstrated
superior blood pressure lowering as compared with losartan (COZAAR). Irbesartan
also has shown better blood pressure reduction than valsartan (DIOVAN).
What
are the side effects of ARBs?
ARBs
are well-tolerated by most individuals. The most common side effects are cough,
elevated potassium levels, low blood pressure, dizziness, headache, drowsiness,
diarrhea, abnormal taste sensation
(metallic or salty taste), and rash. Compared to ACE inhibitors,
cough occurs less often with ARBs. The most serious, but rare, side effects are
kidney failure, liver failure, allergic reactions, a
decrease in white blood cells, and swelling of tissues (angioedema). ARBs
usually are not prescribed for pregnant patients because they may cause birth
defects. Individuals with severe kidney problems and those who have had a severe
reaction to ARBs probably should avoid them.
With which drugs do ARBs interact?
ARBs have
few interactions with other drugs. Since ARBs may increase blood levels of
potassium, the use of potassium supplements, salt substitutes (which often
contain potassium), or other drugs that increase potassium may result in
excessive blood potassium levels. ARBs may also increase the blood concentration
of lithium (ESKALITH) and lead to an increase
in side effects from lithium.
Rifampin reduces the blood levels of losartan, and
fluconazole (DIFLUCAN) reduces the conversion
of losartan to its active form.
These effects could decrease the effects of losartan.
What are the available ARBs?
The
following is a list of currently available ARBs: candesartan (ATACAND),
eprosartan (TEVETAN), irbesartan (AVAPRO), telmisartan
(MYCARDIS), valsartan (DIOVAN), and losartan (COZAAR).
Reference: FDA Prescribing Information
Last Editorial Review: 4/19/2001
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
- Congestive Heart Failure - Read about congestive heart failure symptoms like fatigue, abdomen, leg and ankle swelling, shortness of breath, sleeplessness, increased urination, nausea, abdominal pain, and decreased appetite.
- losartan, Cozaar - Explains the medication losartan (Cozaar), a drug indicated for the treatment of hypertension.
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