18.4 Beta-Adrenergic Blockers
3 min read•june 18, 2024
Beta-blockers are crucial medications for managing and other heart conditions. They work by blocking the effects of stress hormones on the heart and blood vessels, reducing heart rate and blood pressure.
These drugs come with important considerations for nurses and patients. Monitoring vital signs, administering at consistent times, and educating patients on proper use and potential side effects are key aspects of beta-blocker therapy.
Beta-Adrenergic Blockers
Mechanisms of beta-adrenergic blockers
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- Class of medications used to treat hypertension and other cardiovascular conditions by blocking the effects of endogenous ( and ) on
- Reduce by decreasing heart rate and contractility
- Decrease release from the kidneys leading to reduced and levels which helps lower blood pressure
- Reduce peripheral vascular resistance by blocking in blood vessels and preventing vasoconstriction
- (, ) primarily target in the heart while (, ) block both beta-1 and beta-2 receptors throughout the body
- Beta- are a type of G protein-coupled receptor
Physiological Background
- The plays a crucial role in cardiovascular regulation
- are the target of sympathetic nervous system signaling
- Beta-adrenergic receptors and are two main types
- Activation of these receptors triggers intracellular signaling cascades
- Beta-adrenergic receptor activation stimulates
- This leads to increased production of , a second messenger
Effects and interactions of beta-blockers
- Therapeutic effects include lowering blood pressure, reducing the workload on the heart, and decreasing the risk of cardiovascular events (heart attack, stroke)
- Side effects may include (slow heart rate), fatigue and weakness, cold extremities due to decreased peripheral blood flow, in patients with or (more common with non-selective beta-blockers), and hypoglycemia in patients with diabetes as beta-blockers may mask symptoms
- Drug interactions
- can increase the risk of and heart block when combined with beta-blockers
- Antidiabetic medications have an increased risk of hypoglycemia when used with beta-blockers
- may decrease the antihypertensive effect of beta-blockers by retaining sodium and water
Nursing considerations for beta-blockers
- Assess patient's medical history particularly for asthma, COPD, diabetes, and before administering beta-blockers
- Monitor vital signs especially heart rate and blood pressure to ensure therapeutic effect and detect any adverse reactions
- Administer beta-blockers at the same time each day to maintain consistent blood levels and optimize efficacy
- Educate patients on the importance of not abruptly discontinuing beta-blockers as this may cause and worsen cardiovascular symptoms
- Encourage patients to report any side effects or concerns to their healthcare provider promptly for appropriate management
Patient education for beta-blockers
- Explain the purpose and mechanism of action of beta-blockers in managing hypertension by blocking the effects of stress hormones on the heart and blood vessels
- Instruct patients on proper dosing and administration
- Take medication at the same time each day to maintain consistent blood levels
- Do not crush, chew, or break formulations as this can alter the drug's absorption and efficacy
- Advise patients on potential side effects and when to seek medical attention
- Contact healthcare provider if experiencing severe fatigue, dizziness, or difficulty breathing which may indicate an adverse reaction
- Emphasize the importance of regular follow-up appointments to monitor treatment progress and adjust dosage if needed to optimize blood pressure control
- Encourage lifestyle modifications to support hypertension management
- Maintain a healthy diet low in sodium (processed foods) and rich in fruits, vegetables, and whole grains to help lower blood pressure
- Engage in regular physical activity (brisk walking, swimming) as tolerated and approved by healthcare provider to improve cardiovascular health
- Manage stress through relaxation techniques (deep breathing, meditation) to reduce the impact of stress hormones on blood pressure
Key Terms to Review (47)
Adenylyl Cyclase: Adenylyl cyclase is a crucial enzyme involved in the intracellular signaling pathway, particularly in the context of beta-adrenergic receptor activation. It catalyzes the conversion of ATP to the second messenger cyclic AMP (cAMP), which then triggers a cascade of downstream effects that regulate various physiological processes.
Adrenergic receptors: Adrenergic receptors are a class of G protein-coupled receptors targeted by catecholamines like adrenaline and noradrenaline. They play a crucial role in the sympathetic nervous system by modulating physiological responses such as heart rate, blood pressure, and bronchodilation.
Adrenergic Receptors: Adrenergic receptors are a class of G protein-coupled receptors that bind to the neurotransmitters epinephrine (adrenaline) and norepinephrine (noradrenaline). These receptors play a crucial role in the body's sympathetic nervous system, mediating the physiological responses to these neurotransmitters.
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.
Alpha-Adrenergic Receptors: Alpha-adrenergic receptors are a class of G-protein coupled receptors that bind to the neurotransmitter norepinephrine and mediate various physiological responses in the body. These receptors play a crucial role in regulating cardiovascular function, blood pressure, and other autonomic processes.
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.
Asthma: Asthma is a chronic inflammatory disorder of the airways characterized by recurring episodes of breathlessness, wheezing, chest tightness, and coughing. It involves a complex interplay of airway inflammation, bronchial hyperresponsiveness, and airflow obstruction, which can significantly impact respiratory function and quality of life.
Atenolol: Atenolol is a cardioselective beta-blocker medication primarily used to treat high blood pressure, angina, and certain heart rhythm disorders. It works by selectively blocking beta-1 adrenergic receptors, which are predominantly found in the heart, reducing the heart's workload and oxygen demand.
Beta-1 Receptors: Beta-1 receptors are a type of adrenergic receptor found primarily in the heart and kidneys. They play a crucial role in regulating various physiological processes, including heart rate, contractility, and blood pressure, making them an important target for drugs used to treat nervous system disorders and cardiovascular conditions.
Beta-2 Receptors: Beta-2 receptors are a subtype of beta-adrenergic receptors that are primarily located in the smooth muscle cells of the lungs, blood vessels, and other organs. They play a crucial role in the regulation of various physiological processes, particularly in the context of nervous system disorders, beta-adrenergic blockers, and the interplay between adrenergics and anticholinergics.
Beta-adrenergic blockers: Beta-adrenergic blockers, also known as beta-blockers, are medications that reduce blood pressure by blocking the effects of adrenaline on beta receptors in the heart and blood vessels. They are used to treat various cardiovascular conditions including hypertension, angina, and dysrhythmias.
Beta-Adrenergic Blockers: Beta-adrenergic blockers, also known as beta-blockers, are a class of medications that work by blocking the effects of the hormone epinephrine (adrenaline) on beta-adrenergic receptors in the body. This action helps to reduce heart rate, blood pressure, and the workload on the heart, making them an important therapeutic option for various cardiovascular conditions.
Beta-Adrenergic Receptors: Beta-adrenergic receptors are a class of G protein-coupled receptors that bind to the neurotransmitter norepinephrine and the hormone epinephrine. These receptors play a crucial role in the sympathetic nervous system's regulation of various physiological processes, including heart rate, blood pressure, and metabolic functions.
Bradycardia: Bradycardia is a slower than normal heart rate, typically defined as fewer than 60 beats per minute in adults. It can be a sign of an underlying health issue or a side effect of certain medications.
Bradycardia: Bradycardia is a condition characterized by an abnormally slow heart rate, typically less than 60 beats per minute. This term is relevant in the context of various cardiovascular and pharmacological topics, as it can be a side effect or complication associated with certain medications and disease states.
Bronchospasm: Bronchospasm refers to the sudden, involuntary constriction of the smooth muscles lining the bronchi and bronchioles, leading to narrowing of the airways. This phenomenon is a key feature in various respiratory conditions and can significantly impact breathing function.
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.
CAMP: cAMP, or cyclic adenosine monophosphate, is a crucial second messenger molecule that plays a central role in cellular signaling pathways. It is involved in the regulation of various physiological processes, including the effects of beta-adrenergic receptor activation.
Cardiac Output: Cardiac output is the volume of blood pumped by the heart per minute. It is a critical measure of the heart's pumping ability and a key determinant of tissue perfusion and oxygen delivery throughout the body. This term is essential in understanding the fundamental mechanics of the cardiovascular system and its role in various cardiovascular conditions and their management.
Carvedilol: Carvedilol is a non-selective beta-adrenergic blocker with alpha-1 blocking activity, used to treat hypertension and heart failure. It reduces heart rate, myocardial contractility, and blood pressure.
Catecholamines: Catecholamines are a group of neurotransmitters and hormones that play a crucial role in regulating various physiological processes, including cardiovascular function, stress response, and energy metabolism. These chemical messengers are primarily produced in the adrenal glands and the sympathetic nervous system, and they exert their effects by binding to specific receptors on target cells.
COPD: COPD, or Chronic Obstructive Pulmonary Disease, is a progressive lung disease characterized by persistent respiratory symptoms and airflow limitation. It is a significant term in the context of 18.4 Beta-Adrenergic Blockers, 23.2 Introduction to the Lower Respiratory System, 24.2 Antitussives, and 25.3 Xanthines, Leukotriene Modifiers, and Mast Cell Stabilizers, as it impacts the management and treatment of various respiratory conditions.
Coreq: Coreq is a non-selective beta-adrenergic blocker with additional alpha-blocking activity, used primarily in the treatment of hypertension and angina pectoris. It helps to reduce heart rate, myocardial contractility, and blood pressure.
Corgard: Corgard, also known as nadolol, is a non-selective beta-adrenergic blocker used to treat high blood pressure and angina. It works by blocking the action of certain natural substances in your body, such as epinephrine, on the heart and blood vessels.
Epinephrine: Epinephrine, also known as adrenaline, is a hormone and medication that plays a critical role in the body's fight-or-flight response. It is used in medical emergencies to treat conditions like cardiac arrest, anaphylaxis, and severe asthma attacks.
Epinephrine: Epinephrine, also known as adrenaline, is a hormone and neurotransmitter produced by the adrenal glands. It plays a crucial role in the body's fight-or-flight response, preparing the body to handle stressful or dangerous situations. This key term is particularly relevant in the context of various nervous system and cardiovascular drug topics.
Extended-Release: Extended-release, also known as sustained-release or controlled-release, is a drug delivery system designed to release the active pharmaceutical ingredient at a predetermined rate and duration to maintain a constant drug concentration in the body over an extended period of time. This approach aims to improve therapeutic efficacy, patient compliance, and reduce side effects compared to immediate-release formulations.
G Protein-Coupled Receptors: G protein-coupled receptors (GPCRs) are a large family of cell surface receptors that play a crucial role in transmitting extracellular signals into intracellular responses. These receptors are involved in a wide range of physiological processes and are the target of many pharmacological agents, including the beta-adrenergic blockers discussed in Chapter 18.4.
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.
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.
Inderal LA: Inderal LA is a long-acting form of propranolol, a non-selective beta-adrenergic blocker used to treat hypertension and angina. It works by reducing the heart rate and decreasing the force of heart contractions.
Lopressor: Lopressor is a brand name for metoprolol, a beta-adrenergic blocker used to treat hypertension, angina, and certain heart rhythm disorders. It works by reducing the heart rate and the heart's workload.
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.
Metoprolol tartrate: Metoprolol tartrate is a selective beta-1 adrenergic blocker used to treat hypertension and angina. It works by reducing heart rate and myocardial contractility, thus lowering blood pressure.
Nadolol: Nadolol is a non-selective beta-adrenergic blocker used primarily for the management of hypertension and angina pectoris. It decreases heart rate and myocardial oxygen demand, providing relief from cardiac symptoms.
Non-Selective Beta-Blockers: Non-selective beta-blockers are a class of medications that block the action of both beta-1 and beta-2 adrenergic receptors in the body. This broad mechanism of action distinguishes them from selective beta-blockers, which target only one type of beta receptor.
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.
Norepinephrine: Norepinephrine is a neurotransmitter and hormone produced by the adrenal glands and certain neurons in the brain. It plays a crucial role in the body's sympathetic nervous system, responsible for the 'fight-or-flight' response, and is involved in a variety of physiological and psychological processes.
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.
Peripheral Vascular Disease: Peripheral vascular disease (PVD) is a circulatory disorder that affects the blood vessels outside of the heart and brain, typically in the legs and arms. It is characterized by the narrowing or blockage of these blood vessels, which can lead to reduced blood flow and oxygen supply to the affected limbs.
Propranolol: Propranolol is a beta-adrenergic blocking agent, commonly known as a beta-blocker, that is primarily used to treat a variety of cardiovascular and neurological conditions. It works by blocking the effects of the neurotransmitter norepinephrine, which is responsible for the body\'s fight-or-flight response, making it a versatile medication with applications in the nervous system, migraine treatment, and cardiac dysrhythmia management.
Rebound Hypertension: Rebound hypertension is a sudden and severe increase in blood pressure that can occur after the discontinuation or abrupt reduction of certain antihypertensive medications, particularly beta-adrenergic blockers and diuretics. This phenomenon is a result of the body's compensatory mechanisms attempting to restore normal blood pressure levels.
Renin: Renin is an enzyme produced by the kidneys that plays a crucial role in the regulation of blood pressure and fluid balance within the body. It is a key component of the renin-angiotensin-aldosterone system, which is central to the understanding of topics such as Angiotensin-Converting Enzyme (ACE) Inhibitors, Beta-Adrenergic Blockers, and drugs affecting the Renin-Angiotensin-Aldosterone System.
Selective Beta-Blockers: Selective beta-blockers are a class of medications that primarily target and block the effects of the beta-1 adrenergic receptors, which are predominantly found in the heart. This selective action allows them to manage cardiovascular conditions while minimizing the impact on other beta-2 receptors found in the lungs and peripheral vasculature.
Sympathetic Nervous System: The sympathetic nervous system is a division of the autonomic nervous system that is responsible for the body's fight-or-flight response. It prepares the body to respond to perceived threats or stressful situations by increasing heart rate, blood pressure, and breathing rate, while also diverting blood flow away from the digestive system and towards the muscles.
Tenormin: Tenormin, also known as atenolol, is a beta-adrenergic blocker commonly used to treat high blood pressure and angina. It works by slowing the heart rate and reducing the heart's workload.