Angiotensin Receptor Blockers (ARBs)

Angiotensin receptor blockers (ARBs) are medicines. They are most often prescribed to treat high blood pressure, but can be used to treat other conditions. This sheet tells you how ARBs work and how to use them effectively.

How ARBs work

ARBS help reduce blood pressure by blocking a hormone (angiotensin II) produced in the kidneys. Angiotensin II raises blood pressure by constricting arteries and causing the release of another hormone (aldosterone) that retains salt, leading to further blood pressure increase. So, when an ARB blocks angiotensin II, it results in lower blood pressure by dilating arteries and decreasing blood volume by loss of salt.

What conditions ARBs treat

• Blood pressure. Because ARBs help reduce blood pressure, they are most often used to treat high blood pressure (hypertension). They may be prescribed as an alternative to angiotensin-converting enzyme (ACE) inhibitors if certain side effects are developed on ACE inhibitors, such as cough.

• Heart failure. This is when the heart is no longer able to pump enough blood throughout the body. ARBs prevent a rise in blood pressure and lessen strain on the heart. These things help treat heart failure by making it easier for the heart to pump, and improving blood flow.

• Diabetes. This is when the body does not make enough insulin to use the sugar in the blood for energy. Diabetes can damage the blood vessels. This can lead to kidney failure (when the kidneys stop working properly). High blood pressure can also damage the blood vessels. Because ARBs help to lessen blood pressure, they help decrease the risk of blood vessel damage and kidney failure.

Side effects of ARBs

Side effects may occur during the first few days of usage, some of which fade as your body gets used to the medicine. If these side effects persist or worsen, call your healthcare provider. Some side effects may require stopping the medicine right away, as directed by your healthcare provider. Side effects can include:

• Cough

• Low blood pressure

• Dizziness

• Drowsiness

• Diarrhea

• Stuffy nose

• Raised potassium levels

• Swelling in the deep skin layers (angiodema)

Drug interactions

Some medicines affect how other drugs work when taken together. ARBs have few interactions with other drugs. But talk to your healthcare provider if you take any of the following:

• Potassium supplements, salt substitutes, and drugs that increase potassium levels

• Diuretics (“water pills”)

• Lithium

• Cimetidine

• Rifampin

• Fluconazole or ketoconazole

What to tell your doctor before taking ARBs

Your doctor needs to know your health history to safely prescribe medicine for you. Be sure to tell your doctor:

• What medicines you are taking, including over-the-counter types and supplements.

• If you are allergic to any medicines, especially ACE inhibitors.

• If you have or have had other medical problems such as diabetes or heart, kidney, or liver disease.

• If you are pregnant, planning to become pregnant or are breastfeeding.

Note: Do not take ARBs when you’re pregnant or thinking about becoming pregnant. This medicine can harm an unborn baby.

Tips for taking medicines

ARBs need to be taken every day—even when you feel fine. Use the tips below to stay on track.

• Have a routine. Take your medication at the same time each day. This might be with breakfast, when you brush your teeth, or before you walk the dog. If you miss a pill, don’t take two the next time.

• Plan ahead. Refill prescriptions before they run out. Be sure to take enough medication with you when you travel.

• Never change your dosage or stop taking medicine on your own. This can be dangerous. Always talk to your doctor before making any changes in your medication plan.

• Use reminders. Keep medication where you can see it. Put notes on the refrigerator or other places you’ll see them. Using a pillbox can also help.

• Tell your healthcare provider about other medicines or supplements you take. These can react with your medicine. Some cold and flu medicines can also raise blood pressure.