How Do ARBs Work? Plus, 5 More FAQs About These Blood Pressure Medications
Key takeaways:
Angiotensin II receptor blockers (ARBs) are commonly prescribed blood pressure medications. ARBs work by blocking the effects of angiotensin II, a hormone that raises blood pressure.
ARBs start lowering blood pressure within about 3 to 6 hours after taking a dose. People typically take them long term to help lower the risk of heart or kidney-related health complications.
Unlike some other blood pressure medications, ARBs don’t typically cause a dry cough. But they can cause hyperkalemia (high potassium levels).
There are many ways to save on your ARB medications. Many options are available as lower-cost generics. GoodRx can help make your prescription more affordable.
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Table of contents
Angiotensin II receptor blockers (ARBs) are a popular class of medications for heart health. You can tell them apart from other medications by their names. Generic ARB names all end in “-sartan.” Examples include losartan (Cozaar), valsartan (Diovan), and olmesartan (Benicar).
ARBs are commonly prescribed to treat high blood pressure (hypertension). But they can also help with other health conditions, such as heart failure and chronic kidney disease (CKD). Below, we’ll explain how ARBs work for these conditions and answer five more frequently asked questions about these medications.
1. How do ARBs work?
ARBs work by blocking angiotensin II from attaching to its receptors (chemical binding sites). Angiotensin II is a hormone that tells your blood vessels to squeeze tighter. This can lead to higher blood pressure.
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Angiotensin II also signals the body to release another hormone called aldosterone. Aldosterone tells your body to hold on to more salt (sodium) and water, which can also raise blood pressure.
In order to work, angiotensin II has to bind to a specific receptor. ARBs block that receptor. This helps prevent angiotensin II from telling your blood vessels to tighten and lowers levels of aldosterone. And this helps lower blood pressure.
These actions can also help take strain off the heart and kidneys. That’s why ARBs can also help manage heart failure, CKD, and more.
Good to know: ARBs may be less effective at lowering blood pressure in Black adults. Other medications, such as thiazide diuretics and calcium channel blockers, are typically preferred. However, ARBs are recommended for Black adults who have other conditions that impact the heart, such as heart failure or diabetes.
2. What are ARBs used for?
ARBs can be a first-choice option for treating hypertension. You can take an ARB by itself or in combination with other blood pressure medications. All ARBs are FDA approved to treat hypertension in adults. Experts also recommend some ARBs for hypertension in children and teens, such as losartan and valsartan.
Additionally, ARBs are used to treat other health conditions, including:
Heart failure
CKD
Kidney protection for people with diabetes
To improve survival after a heart attack
To lower the risk of heart attack or stroke due to left ventricular hypertrophy (thickening of the walls of the heart)
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Keep in mind that specific FDA-approved uses for ARBs vary between medications.
3. How long do ARBs take to work for hypertension?
ARBs typically start lowering blood pressure around 3 to 6 hours after taking a dose. But you’ll need to take an ARB daily for a few weeks to get consistent results.
In general, ARBs work best for hypertension when combined with lifestyle changes. For example, your healthcare provider may recommend certain exercises to support heart health. They may also suggest lowering your sodium intake.
Talk to your provider about getting the most mileage out of your ARB.
4. Can you stop taking ARBs?
Usually not. ARBs are typically long-term medications. Many people take them for years or even the rest of their lives. You shouldn't stop taking an ARB unless your healthcare provider has told you to.
Stopping any blood pressure medication too suddenly can be dangerous, especially if you’ve been taking it for a while and your body is used to it. It can lead to severely high blood pressure and potentially life-threatening complications, such as a heart attack or stroke.
5. Do ARBs cause a dry cough?
No, ARBs don’t usually cause a dry cough. This side effect is more common with angiotensin-converting enzyme (ACE) inhibitors, such as lisinopril (Zestril, Qbrelis). In clinical trials, about 3% of people taking ARBs developed a dry cough, compared to nearly 10% of people taking ACE inhibitors.
ACE inhibitors and ARBs work a little differently. ACE inhibitors can cause a buildup of two proteins: bradykinin and substance P. These proteins can irritate the airways, causing a dry cough. ARBs don’t seem to affect bradykinin and substance P, so coughing is less likely.
Dry cough is a common reason people have trouble taking an ACE inhibitor. In these cases, ARBs can be a great alternative.
6. Do ARBs cause hyperkalemia (high potassium)?
Yes. ARBs can cause hyperkalemia (high potassium levels). This side effect happens because ARBs lower aldosterone levels. Aldosterone normally signals to the kidneys to get rid of potassium. Less aldosterone means more potassium stays in the body.
You’re more likely to experience hyperkalemia with ARBs if you have kidney problems or if you take other medications that raise potassium levels. Typically, mild hyperkalemia causes no symptoms. However, very high potassium can cause serious problems, such as abnormal heart rhythms.
Your healthcare provider will likely check your blood potassium levels from time to time while you’re taking an ARB. Going for these blood tests can help your provider catch and manage hyperkalemia early.
How to save on your ARB prescription
There are many ways to save on your ARB medication. GoodRx can help you navigate your options, which may include GoodRx discounts, copay savings cards, and patient assistance programs. You can find ARB prices for as low as $15 with a free GoodRx discount.
There are also ways to save on certain brand-name products. For instance, anyone with a valid prescription can use GoodRx to purchase a 30-day supply of Edarbi (azilsartan) at an exclusive cash price as low as $120 and a 30-day supply of Atacand (candesartan) at an exclusive cash price of $99.
The bottom line
Angiotensin II receptor blockers (ARBs) are commonly prescribed blood pressure medications. ARBs block the effects of the hormone angiotensin II, a hormone that can raise blood pressure.
These medications start working within a few hours. But many people have to take them long term to get the most benefit.
ARBs are unlikely to cause a dry cough. But they can raise your potassium levels. Going for recommended blood tests on time can help your healthcare provider make sure your potassium levels don't rise too high.
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References
Abraham, H. M. A., et al. (2016). The comparative efficacy and safety of the angiotensin receptor blockers in the management of hypertension and other cardiovascular diseases. Drug Safety.
American Heart Association. (2020). What is left ventricular hypertrophy (LVH)?
Flynn, J. T., et al. (2017). Clinical practice guideline for screening and management of high blood pressure in children and adolescents. Pediatrics.
Hill, R. D., et al. (2023). Angiotensin II receptor blockers (ARB). StatPearls.
Matchar, D. B., et al. (2008). Systematic review: Comparative effectiveness of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers for treating essential hypertension. Annals of Internal Medicine.
Pinto, B., et al. (2020). ACEI-induced cough: A review of current evidence and its practical implications for optimal CV risk reduction. Indian Heart Journal.
Scott, J. H., et al. (2023). Physiology, aldosterone. StatPearls.
Unger, T., et al. (2020). 2020 International Society of Hypertension global hypertension practice guidelines. Hypertension.
You and Your Hormones. (2019). Angiotensin.
You and Your Hormones. (2021). Aldosterone.
