18.3 Angiotensin II Receptor Blockers (ARBs)
4 min read•june 18, 2024
are a powerful class of drugs that lower by blocking receptors. They relax blood vessels, reduce fluid retention, and ease strain on the heart, making them effective for treating and related conditions.
Compared to other blood pressure medications, ARBs are well-tolerated with fewer side effects. They work similarly to but don't cause the dry cough some patients experience. Proper monitoring and patient education are key for safe, effective use.
Mechanism of Action and Efficacy of ARBs
Mechanism of action for ARBs
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- ARBs selectively block angiotensin II type 1 (AT1) receptors prevents angiotensin II from binding to and inhibits angiotensin II-mediated (narrowing of blood vessels) and secretion (hormone that promotes sodium and water retention)
- Reduces peripheral vascular resistance decreases arterial pressure and lowers blood pressure by allowing blood vessels to relax and widen
- Promotes increases blood flow to tissues (muscles, organs) and reduces cardiac workload (strain on the heart)
- Decreases sodium and water retention reduces plasma volume (fluid in the bloodstream) and contributes to blood pressure reduction by preventing the body from holding onto excess salt and water
ARBs vs other antihypertensive drugs
- ARBs have similar efficacy to ACE inhibitors (lisinopril, enalapril) in lowering blood pressure as both classes target the () which regulates blood pressure
- ARBs have fewer side effects compared to ACE inhibitors with a lower incidence of dry cough and (swelling of face, tongue, or throat) making them better tolerated by patients who experience these side effects with ACE inhibitors
- ARBs have comparable efficacy to other antihypertensive classes such as (amlodipine), (), and () with the choice depending on patient characteristics (age, race) and comorbidities (diabetes, kidney disease)
- Side effects of ARBs are generally mild including dizziness, headache, and fatigue but can cause (high potassium levels) and renal dysfunction (decreased kidney function) in high-risk patients (elderly, diabetic, or those with pre-existing renal impairment)
Pharmacokinetics and Adverse Effects of ARBs
- : ARBs are generally well-absorbed orally, with peak plasma concentrations reached within 1-4 hours
- Most ARBs have a long half-life, allowing for once-daily dosing
- ARBs are primarily metabolized by the liver and excreted through bile and urine
- : Common side effects include dizziness, headache, and fatigue
- Serious may include hyperkalemia, hypotension, and impaired (especially in patients with pre-existing kidney disease)
- ARBs are contraindicated during pregnancy due to potential fetal harm
Nursing Considerations and Patient Education
Nursing considerations for ARB administration
- Monitor blood pressure and heart rate regularly assess for (drop in blood pressure upon standing), especially in elderly or volume-depleted patients (dehydrated) and adjust dosage as needed to achieve target blood pressure
- Monitor renal function and electrolytes check (waste product filtered by kidneys) and potassium levels periodically and use caution in patients with renal impairment or at risk for hyperkalemia
- Be aware of potential drug interactions avoid concomitant use with (spironolactone) or potassium supplements due to increased risk of hyperkalemia and use caution when combining with (), as they may attenuate the antihypertensive effect and increase the risk of renal dysfunction
- Administer ARBs at the same time each day for consistent timing helps maintain stable blood levels and improves efficacy with some ARBs taken with or without food, while others have specific recommendations (take on an empty stomach)
Patient education for ARB use
- Educate patients on the purpose and benefits of ARB therapy emphasize the importance of long-term adherence for blood pressure control and cardiovascular risk reduction (heart attack, stroke) and discuss potential side effects and when to seek medical attention
- Encourage patients to take ARBs as prescribed advise patients not to skip doses or stop taking the medication without consulting their healthcare provider and suggest strategies to improve adherence, such as using pill boxes or setting reminders (phone alarms)
- Promote lifestyle modifications to enhance the effectiveness of ARB therapy recommend a low-sodium diet (limit salt intake) to help control blood pressure, encourage regular physical activity (brisk walking, swimming), as it can improve cardiovascular health and aid in weight management, and advise patients to maintain a healthy weight and quit smoking, if applicable
- Instruct patients to monitor their blood pressure at home teach proper technique for measuring blood pressure (seated, arm supported, cuff at heart level) and provide guidance on interpreting results and when to report abnormal readings to their healthcare provider
- Emphasize the importance of regular follow-up visits ensure patients understand the need for periodic monitoring of blood pressure, renal function, and electrolytes and encourage patients to discuss any concerns or questions with their healthcare provider
- Explain that ARBs are primarily used to treat hypertension and may also be beneficial for patients with certain cardiovascular diseases or diabetes
Key Terms to Review (42)
ACE Inhibitors: ACE (Angiotensin-Converting Enzyme) inhibitors are a class of medications that work by blocking the action of the angiotensin-converting enzyme, which is responsible for converting angiotensin I into angiotensin II, a potent vasoconstrictor. By inhibiting this enzyme, ACE inhibitors help lower blood pressure and reduce the workload on the heart.
Adverse effects: Adverse effects are unintended and harmful outcomes resulting from medication or other interventions. They can range from mild to severe and may require medical attention.
Adverse Effects: Adverse effects, also known as side effects, are unintended and undesirable consequences that can occur during or after the use of a drug or medication. These effects can range from mild discomfort to serious and potentially life-threatening conditions, and they are an important consideration in the context of drug classifications, pharmacokinetics, pharmacodynamics, drug administration, and the use of specific drug classes like angiotensin II receptor blockers (ARBs).
Aldosterone: Aldosterone is a hormone produced by the adrenal glands that regulates sodium and potassium balance in the blood. It plays a crucial role in controlling blood pressure.
Aldosterone: Aldosterone is a mineralocorticoid hormone produced by the adrenal glands that plays a crucial role in maintaining fluid and electrolyte balance in the body. It is a key component in the regulation of homeostasis, the renin-angiotensin-aldosterone system, and the management of various cardiovascular and renal conditions.
Angioedema: Angioedema is a sudden, rapid swelling of the deeper layers of the skin and mucous membranes, often caused by an allergic reaction or certain medications. It is a serious medical condition that can affect various parts of the body, including the face, lips, tongue, throat, and extremities.
Angiotensin II: Angiotensin II is a potent vasoconstrictor hormone that plays a central role in the regulation of blood pressure and fluid balance within the body. It is a key component of the renin-angiotensin-aldosterone system (RAAS), which is a complex physiological pathway involved in maintaining homeostasis.
Angiotensin II Receptor Blockers: Angiotensin II Receptor Blockers (ARBs) are a class of medications that work by blocking the action of angiotensin II, a hormone that plays a crucial role in regulating blood pressure and fluid balance in the body. By inhibiting the effects of angiotensin II, ARBs help to lower blood pressure and reduce the strain on the cardiovascular system.
Angiotensin II receptor blockers (ARBs): Angiotensin II receptor blockers (ARBs) are a class of drugs that inhibit the effects of angiotensin II by blocking its binding to the angiotensin II type 1 receptor. They are primarily used to treat hypertension and heart failure.
ARBs: ARBs, or Angiotensin II Receptor Blockers, are a class of medications that work by blocking the action of angiotensin II, a hormone that plays a crucial role in regulating blood pressure and fluid balance within the body. ARBs are commonly used to treat hypertension, heart failure, and other cardiovascular conditions.
AT1 Receptors: AT1 receptors are a type of angiotensin II receptor that play a crucial role in the regulation of blood pressure and fluid balance within the body. These receptors are the primary targets of angiotensin II receptor blockers (ARBs), a class of drugs used to treat hypertension and other cardiovascular conditions.
Atacand: Atacand is the brand name for candesartan, an angiotensin II receptor blocker (ARB) used to treat high blood pressure and heart failure. It works by blocking the action of angiotensin II, which helps relax blood vessels and lower blood pressure.
Beta-Blockers: Beta-blockers are a class of medications that work by blocking the effects of the hormone epinephrine (adrenaline) on the body. They are primarily used to treat various cardiovascular conditions, such as hypertension, angina, and heart failure, by reducing the heart's workload and oxygen demand.
Black clients: Black clients are patients who identify as Black or African American. Special considerations in pharmacology may be necessary due to genetic, socio-economic, and cultural factors that affect drug efficacy and safety.
Blood Pressure: Blood pressure is the force exerted by the blood against the walls of the blood vessels, primarily the arteries, as the heart pumps blood throughout the body. It is a critical physiological parameter that reflects the overall health and functioning of the cardiovascular system.
Calcium Channel Blockers: Calcium channel blockers are a class of medications that work by inhibiting the movement of calcium ions across cell membranes, particularly in the heart and blood vessels. This mechanism of action makes them useful in the management of various cardiovascular conditions, including dysrhythmias, hypertension, and angina.
Candesartan: Candesartan is an angiotensin II receptor blocker (ARB) used to treat hypertension and heart failure. It works by blocking the action of angiotensin II, leading to vasodilation and reduced blood pressure.
Cardiovascular Disease: Cardiovascular disease (CVD) is a group of disorders that affect the heart and blood vessels, including conditions such as coronary artery disease, heart attack, stroke, and high blood pressure. It is a major cause of morbidity and mortality worldwide, and understanding its relationship to topics like Angiotensin II Receptor Blockers (ARBs) and Bile Acid Sequestrants, Fibrates, and Niacin is crucial for healthcare professionals.
Cozaar: Cozaar is the brand name for losartan, an angiotensin II receptor blocker (ARB) used to treat hypertension and reduce the risk of stroke. It works by relaxing blood vessels so blood can flow more easily.
Diovan: Diovan is a brand name for valsartan, an angiotensin II receptor blocker (ARB). It is used to treat high blood pressure and heart failure.
Diuretics: Diuretics are a class of medications that increase the excretion of water and electrolytes, primarily sodium, from the body. They are commonly used to manage conditions related to fluid imbalance, such as hypertension, heart failure, and edema.
Furosemide: Furosemide is a potent loop diuretic medication used to treat fluid overload conditions, such as edema and congestive heart failure. It works by inhibiting the reabsorption of sodium, chloride, and water in the thick ascending limb of the loop of Henle in the kidneys, leading to increased urine output and fluid loss.
Grades of hypertension: Grades of hypertension classify the severity of high blood pressure based on systolic and diastolic measurements. These grades help guide treatment decisions and risk assessment.
Hyperkalemia: Hyperkalemia is a medical condition characterized by an abnormally high concentration of potassium (K+) in the blood. This electrolyte imbalance can have significant impacts on the body's homeostasis and various physiological processes, including cardiac function, fluid balance, and nerve impulse transmission.
Hypertension: Hypertension, also known as high blood pressure, is a chronic medical condition in which the blood pressure in the arteries is elevated, increasing the risk of heart disease, stroke, and other health complications. It is a key term that is closely connected to various topics in pharmacology, including the management of cardiovascular conditions and the use of specific drug classes to control blood pressure.
Ibuprofen: Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) commonly used to reduce inflammation, pain, and fever. It is a key medication in the context of various medical topics, including the inflammatory response, pain management, hypertension treatment, and diuretic therapy.
Losartan: Losartan is an angiotensin II receptor blocker (ARB) used to treat hypertension and heart failure. It works by relaxing blood vessels, making it easier for the heart to pump blood.
Metoprolol: Metoprolol is a beta-adrenergic blocking agent, commonly known as a beta-blocker, that is primarily used to treat various cardiovascular conditions, including hypertension, angina, and certain types of arrhythmias. It works by selectively blocking the beta-1 receptors in the heart, reducing the heart's workload and oxygen demand.
Micardis: Micardis is a brand name for telmisartan, an angiotensin II receptor blocker (ARB) used to treat high blood pressure. It works by relaxing blood vessels so that blood can flow more easily.
Nonsteroidal anti-inflammatory drugs (NSAIDs): Nonsteroidal anti-inflammatory drugs (NSAIDs) are medications that reduce inflammation, pain, and fever without the use of steroids. They inhibit cyclooxygenase enzymes (COX-1 and COX-2), which are involved in the production of prostaglandins.
NSAIDs: NSAIDs, or Non-Steroidal Anti-Inflammatory Drugs, are a class of medications that are widely used to reduce inflammation, alleviate pain, and lower fever. They work by inhibiting the production of prostaglandins, which are key mediators of the inflammatory response. NSAIDs are commonly employed in the management of various conditions, including arthritis, menstrual cramps, headaches, and post-operative pain.
Orthostatic Hypotension: Orthostatic hypotension is a sudden drop in blood pressure that occurs when an individual stands up from a sitting or lying position. This condition can lead to dizziness, lightheadedness, and even fainting, and is particularly relevant in the context of various medical conditions and drug therapies.
Pharmacokinetics: Pharmacokinetics is the study of how the body affects a drug, including the processes of absorption, distribution, metabolism, and elimination. It examines the movement of drugs within the body and how these processes impact the drug's concentration and duration of action.
Potassium-Sparing Diuretics: Potassium-sparing diuretics are a class of medications that work to increase the excretion of sodium and water from the body while simultaneously preventing the loss of potassium. This unique mechanism of action makes them particularly relevant in the context of angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), and other diuretic therapies.
RAAS: RAAS, or the Renin-Angiotensin-Aldosterone System, is a complex hormonal cascade that plays a crucial role in regulating blood pressure, fluid balance, and electrolyte homeostasis within the body. This system is closely interconnected with the topics of Angiotensin II Receptor Blockers (ARBs) and drugs affecting the Renin-Angiotensin-Aldosterone System.
Renal Function: Renal function refers to the ability of the kidneys to filter blood, regulate fluid and electrolyte balance, and excrete waste products from the body. It is a crucial physiological process that maintains homeostasis and supports various bodily systems.
Renin-Angiotensin-Aldosterone System: The renin-angiotensin-aldosterone system (RAAS) is a complex physiological mechanism that regulates blood pressure, fluid balance, and electrolyte homeostasis in the body. It is a crucial system involved in the management of hypertension, heart failure, and other cardiovascular and renal conditions.
Serum Creatinine: Serum creatinine is a chemical compound that is produced naturally in the body as a byproduct of muscle metabolism. It is filtered out of the blood by the kidneys and excreted in urine, making it a useful indicator of kidney function.
Telmisartan: Telmisartan is an angiotensin II receptor blocker (ARB) used primarily to treat high blood pressure and reduce cardiovascular risk. It works by relaxing blood vessels, making it easier for the heart to pump blood.
Valsartan: Valsartan is an Angiotensin II receptor blocker (ARB) used primarily to treat high blood pressure and heart failure. It works by blocking the action of angiotensin II, a hormone that causes blood vessels to constrict.
Vasoconstriction: Vasoconstriction is the narrowing or constriction of blood vessels, specifically the arteries and arterioles, which leads to a decrease in blood flow and blood pressure. This physiological process is an important mechanism in the regulation of blood flow and blood pressure throughout the body.
Vasodilation: Vasodilation refers to the widening or dilation of blood vessels, particularly the arteries and arterioles. This process leads to increased blood flow and reduced vascular resistance, which can have significant implications in various physiological and pharmacological contexts.