18.5 Calcium Channel Blockers
3 min read•june 18, 2024
are key players in managing cardiovascular issues. They work by blocking calcium influx into cells, leading to vasodilation and reduced heart workload. This helps lower blood pressure and ease angina symptoms.
These drugs come in different classes, each with unique effects on the heart and blood vessels. While they're effective, they can cause side effects like edema and dizziness. Nurses play a crucial role in monitoring patients and providing education on proper use.
Calcium Channel Blockers
Mechanism of calcium channel blockers
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- Block in vascular smooth muscle cells and cardiomyocytes prevents calcium influx into cells reducing intracellular calcium concentration
- Vascular smooth muscle effects include:
- Vasodilation of peripheral arteries and arterioles decreases lowering blood pressure
- Reduces afterload on the heart decreasing cardiac workload
- Cardiac effects include:
- decreases contractility
- decreases heart rate
- Reduced
- Coronary artery dilation increases coronary blood flow improving myocardial oxygen supply helping alleviate angina symptoms (chest pain)
Cellular mechanisms and physiological effects
- Calcium channel blockers target , which are crucial for initiating the in excitable cells
- Inhibition of calcium influx disrupts in cardiac and smooth muscle cells
- In vascular smooth muscle, this leads to relaxation and vasodilation
- Effects on the contribute to their antiarrhythmic properties
Classes of calcium channel blockers
- (, ) are potent peripheral vasodilators with minimal cardiac effects primarily used for
- include:
- () provide moderate peripheral vasodilation and cardiac effects used for hypertension and angina
- () have minimal peripheral vasodilation but potent cardiac effects used for angina, hypertension, and (irregular heartbeat)
Side effects of calcium channel blockers
- Common side effects include , headache, dizziness, flushing, constipation (more common with verapamil), and (more common with non-dihydropyridines)
- Drug interactions:
- (, ) increase levels risking enhanced side effects
- (, phenytoin) decrease calcium channel blocker levels reducing efficacy
- have additive negative chronotropic and inotropic effects increasing risk of and heart block
- Verapamil and increase digoxin levels requiring monitoring for
Nursing considerations for calcium channel blockers
- Nursing considerations:
- Monitor blood pressure and heart rate regularly
- Assess for signs and symptoms of (low blood pressure) and bradycardia (slow heart rate)
- Monitor for peripheral edema (swelling)
- Evaluate patient's response to therapy
- Be aware of potential drug interactions
- Patient education:
- Emphasize the importance of taking medication as prescribed
- Advise patients to report side effects such as dizziness or edema
- Encourage lifestyle modifications (diet, exercise) for hypertension management
- Instruct patients to avoid due to CYP3A4 inhibition
- Advise patients to rise slowly from sitting or lying positions to minimize (dizziness upon standing)
- Educate patients on the signs and symptoms of hypotension and bradycardia instructing them to contact their healthcare provider if these occur
Key Terms to Review (46)
Action potential: An action potential is a rapid, temporary change in the electrical membrane potential of a cell. It is essential for the conduction of electrical impulses in cardiac and nerve cells.
Action Potential: An action potential is a rapid, transient electrical signal that propagates along the membrane of an excitable cell, such as a neuron or muscle cell. It is the fundamental unit of communication in the nervous system, allowing for the transmission of information between different parts of the body.
Amlodipine: Amlodipine is a calcium channel blocker used to treat high blood pressure and angina. It works by relaxing blood vessels, allowing for easier blood flow and reduced heart workload.
Arrhythmias: Arrhythmias refer to any abnormal or irregular heart rhythm that occurs due to disruptions in the electrical activity of the heart. These disturbances in the heart's normal pacing can lead to a wide range of symptoms and potentially serious complications if left untreated.
Benzothiazepines: Benzothiazepines are a class of heterocyclic organic compounds that share a common benzothiazepine ring structure. They are closely related to the benzodiazepine class of drugs and have similar pharmacological effects, primarily acting as calcium channel blockers.
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 adults: Black adults are individuals of African descent or heritage, often focusing on health disparities and unique physiological responses in medical studies.
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.
Calan SR: Calan SR is a sustained-release formulation of verapamil, a calcium channel blocker used to manage hypertension, angina, and certain types of dysrhythmias. It works by inhibiting the influx of calcium ions into cardiac and smooth muscle cells.
Calcium channel blocker: Calcium channel blockers are medications that inhibit the movement of calcium ions through calcium channels, primarily in the heart and blood vessels. They are used to manage hypertension, angina, and certain dysrhythmias.
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.
Cardene: Cardene (nicardipine) is a calcium channel blocker used to treat high blood pressure and angina. It works by relaxing blood vessels so the heart doesn't have to pump as hard.
Cardiac Conduction System: The cardiac conduction system is the specialized network of tissues responsible for the coordinated contraction of the heart chambers. It ensures the efficient and synchronized movement of electrical impulses through the heart, enabling the coordinated pumping action that circulates blood throughout the body.
Cardizem: Cardizem is a brand name for diltiazem, a calcium channel blocker used to treat hypertension, angina, and certain types of arrhythmias. It works by relaxing the muscles of your heart and blood vessels.
CYP3A4 Inducers: CYP3A4 inducers are substances that increase the activity and expression of the CYP3A4 enzyme, a member of the cytochrome P450 enzyme system responsible for the metabolism of many drugs. This can lead to increased clearance and reduced effectiveness of drugs that are substrates of CYP3A4, an important consideration in the context of calcium channel blockers and phosphodiesterase 5 inhibitors.
CYP3A4 Inhibitors: CYP3A4 inhibitors are a class of drugs or substances that reduce the activity or expression of the CYP3A4 enzyme, a key player in the metabolism of many medications. This interaction can lead to increased blood levels and potential toxicity of drugs that are primarily metabolized by CYP3A4, making CYP3A4 inhibitors an important consideration in pharmacotherapy across various therapeutic areas.
Digoxin Toxicity: Digoxin toxicity refers to the adverse effects that can occur when the concentration of the cardiac glycoside medication digoxin reaches toxic levels in the body. This can happen due to overdose, drug interactions, or impaired digoxin clearance, and can have serious consequences for patients, especially those with heart conditions.
Dihydropyridines: Dihydropyridines are a class of calcium channel blockers that work by inhibiting the influx of calcium ions into the smooth muscle cells of the blood vessels, leading to vasodilation and a reduction in blood pressure. They are a subclass of calcium channel blockers that are commonly used to treat hypertension, angina, and other cardiovascular conditions.
Diltiazem: Diltiazem is a calcium channel blocker used to treat hypertension, angina, and certain types of arrhythmias. It works by relaxing the muscles of your heart and blood vessels.
Diltiazem: Diltiazem is a calcium channel blocker medication primarily used to treat cardiovascular conditions such as angina, hypertension, and certain types of arrhythmias. It works by blocking the movement of calcium into the muscle cells of the heart and blood vessels, resulting in vasodilation and reduced workload on the heart.
Erythromycin: Erythromycin is a macrolide antibiotic used to treat a variety of bacterial infections. It works by inhibiting bacterial protein synthesis, preventing the growth and spread of harmful microorganisms. Erythromycin's versatility makes it an important drug in the treatment of conditions related to calcium channel blockers, statins, ocular anti-inflammatories and anti-infectives, as well as acne drugs.
Excitation-Contraction Coupling: Excitation-contraction coupling is the process by which an electrical signal, or action potential, triggers the mechanical contraction of a muscle fiber. This coupling of electrical and mechanical events is essential for the proper functioning of skeletal, cardiac, and smooth muscles throughout the body.
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.
Grapefruit Juice: Grapefruit juice is a citrus fruit juice extracted from the pulp and flesh of the grapefruit. It is known to have significant interactions with certain medications, particularly calcium channel blockers, due to its ability to inhibit specific enzymes involved in drug metabolism.
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.
Hypotension: Hypotension is a medical condition characterized by an abnormally low blood pressure, where the systolic blood pressure falls below 90 mmHg and the diastolic blood pressure falls below 60 mmHg. This can have significant implications on the body's ability to circulate blood and deliver oxygen and nutrients to vital organs.
Ketoconazole: Ketoconazole is a broad-spectrum antifungal medication used to treat a variety of fungal infections. It works by disrupting the synthesis of ergosterol, a critical component of the fungal cell membrane, thereby inhibiting the growth and proliferation of fungal organisms.
L-type Calcium Channels: L-type calcium channels are a class of voltage-gated calcium channels that are primarily found in the cell membranes of cardiac muscle, smooth muscle, and certain endocrine cells. These channels play a crucial role in regulating calcium influx, which is essential for various physiological processes such as muscle contraction, hormone secretion, and signal transduction.
Myocardial Oxygen Demand: Myocardial oxygen demand refers to the amount of oxygen required by the heart muscle (myocardium) to meet its metabolic needs and maintain proper function. It is a critical factor in understanding the pathophysiology and management of various cardiovascular conditions, including hypertension, angina, and the effects of certain drug therapies.
Negative Chronotropic Effect: The negative chronotropic effect refers to the ability of a drug or substance to decrease the heart rate, or slow down the beating of the heart. This is an important consideration when discussing the actions of certain medications, particularly those that target the cardiovascular system.
Negative Inotropic Effect: A negative inotropic effect refers to the reduction or decrease in the contractility or force of cardiac muscle contraction. This effect is particularly relevant in the context of calcium channel blockers, as they can exert a negative inotropic influence on the heart.
Nicardipine: Nicardipine is a calcium channel blocker that relaxes and widens blood vessels, making it easier for the heart to pump. It is used to treat hypertension and angina.
Nifedipine: Nifedipine is a calcium channel blocker primarily used to treat hypertension and angina. It works by relaxing blood vessels, which allows blood to flow more easily.
Non-dihydropyridines: Non-dihydropyridines are a class of calcium channel blockers that differ from the dihydropyridine class in their chemical structure and pharmacological properties. These agents are primarily used in the management of cardiovascular conditions, such as hypertension and angina pectoris.
Norvasc: Norvasc is a brand name for the drug amlodipine, a calcium channel blocker used to treat hypertension and angina. It works by relaxing blood vessels, improving blood flow, and reducing the heart's workload.
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.
Peripheral Edema: Peripheral edema refers to the abnormal accumulation of fluid in the tissues, typically in the lower extremities such as the legs, ankles, and feet. This condition can occur due to various underlying medical conditions and can have implications in the context of calcium channel blockers and renal-associated fluid volume excess.
Peripheral Vascular Resistance: Peripheral vascular resistance refers to the resistance to blood flow in the peripheral blood vessels, primarily the arterioles and capillaries. This resistance is a crucial factor in determining blood pressure and plays a significant role in the regulation of blood flow throughout the body, particularly in the context of hypertension, angina, and shock management.
Phenylalkylamines: Phenylalkylamines are a class of organic compounds characterized by the presence of a phenyl (benzene) ring attached to an alkylamine group. These compounds have diverse pharmacological properties and are found in various medications, particularly in the context of calcium channel blockers.
Procardia: Procardia is a brand name for nifedipine, a calcium channel blocker used to treat hypertension and angina. It works by relaxing blood vessels, making it easier for the heart to pump blood.
Rifampin: Rifampin is a broad-spectrum antibiotic that is widely used in the treatment of various bacterial infections, including tuberculosis. It is a potent inducer of the cytochrome P450 enzyme system, which can significantly impact the pharmacokinetics and pharmacodynamics of other drugs, as well as the management of conditions like calcium channel blocker therapy, anticoagulation, and phosphodiesterase 5 inhibitor usage.
Smooth Muscle Relaxation: Smooth muscle relaxation refers to the process by which the involuntary, non-striated muscles that line various organs and blood vessels in the body, such as the gastrointestinal tract, urinary bladder, and blood vessels, become less tense or contracted, allowing for improved function and blood flow.
Verapamil: Verapamil is a calcium channel blocker used to treat hypertension, angina, and certain types of cardiac dysrhythmias. It works by inhibiting the influx of calcium ions into cardiac and smooth muscle cells, thereby reducing heart rate and dilating blood vessels.
Verelan: Verelan is a brand name for verapamil, a calcium channel blocker used to treat high blood pressure and angina. It works by relaxing blood vessels and reducing the workload on the heart.
Voltage-Gated Channels: Voltage-gated channels are specialized ion channels in the cell membrane that open or close in response to changes in the electrical potential across the membrane. These channels play a crucial role in the generation and propagation of action potentials, which are the basis for electrical signaling in excitable cells like neurons and muscle fibers.