Angiotensin Receptor Blockers (ARBs)

How ARBs work

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

What conditions ARBs are used to treat

• Blood pressure. Because ARBs help reduce blood pressure, they are most often used to treat high blood pressure (hypertension). They may be prescribed instead of angiotensin-converting enzyme (ACE) inhibitors if you have side effects from ACE inhibitors, such as a frequent cough.

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

• Diabetes. This means that the body doesn't 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 lower 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 use. Some fade as your body gets used to the medicine. If these side effects get worse or don't go away, call your health care provider. Some side effects may require stopping the medicine right away, as directed by your provider. Side effects can include:

• A cough.

• Low blood pressure.

• Dizziness.

• Drowsiness.

• Diarrhea.

• A stuffy nose.

• Raised potassium levels.

• Swelling in the deep skin layers (angioedema).

Drug interactions

Some medicines affect how other medicines work when taken together. ARBs have few interactions with other medicines. Talk with your health care provider if you take:

• Potassium supplements, salt substitutes, and medicines that increase potassium levels.

• Water pills (diuretics).

• Lithium.

• Cimetidine.

• Rifampin.

• Fluconazole or ketoconazole.

What to tell your provider before taking ARBs

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

• What medicines you take, including over-the-counter types, vitamins, 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, are planning to become pregnant, or are breastfeeding.

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

Tips for taking medicines

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

• Have a routine. Take your medicine 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 2 the next time.

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

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

• Use reminders. Keep medicine where you can see it. Put notes on the refrigerator or other places you’ll see them. Using a pillbox can also help. Setting a reminder on your watch or using a smartphone app can also help.

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

When should I call my doctor?

Contact your health care provider right away if you take ARBs and have:

• A chronic dry cough.

• Throat fullness.

• Face or lip swelling.

• Chronic diarrhea and weight loss.

• A major change in how much urine you produce.

Call 911

Call 911 if you have:

• Signs of an allergic reaction. These include a rash, itching, swelling, and trouble breathing.

• Chest pain.

• Shortness of breath.

• Fainting (loss of consciousness).