cardiovascular drug
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What are cardiovascular drugs?
Cardiovascular drugs are medicines that impact the function of the heart and blood vessels and are among the most widely used drugs in medicine. They may be prescribed for disorders such as hypertension (high blood pressure), angina pectoris, heart failure, and arrhythmias.
Drugs can affect heart function by altering the force of heart muscle contraction, the frequency, and the regularity of the heartbeat. Some act on blood vessels, causing them to constrict or relax to affect blood pressure.
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Why are cardiovascular drugs prescribed?
Cardiovascular drugs treat conditions affecting the heart and blood vessels. They address disorders like hypertension (high blood pressure), angina pectoris (chest pain from inadequate blood flow), heart failure and arrhythmias (disturbances of cardiac rhythm). These drugs can influence the force of heart muscle contraction, heart rate, or the regularity of the heartbeat. Some act on blood vessels, causing them to constrict or relax to regulate blood pressure. Because cardiovascular diseases are common, these drugs are among the most widely used in medicine.
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What are some common types of cardiovascular drugs?
Cardiovascular drugs affect heart and blood vessel function and are among the most widely used medications. They treat conditions such as high blood pressure, chest pain, heart failure, and arrhythmias.
Common types include:
* Antiplatelet drugs These interfere with platelet aggregation and clot formation, reducing heart attack damage and immediate reinfarction.
* Statins These lower cholesterol levels and may also lower blood pressure by promoting blood vessel relaxation. They can stabilize plaques in artery walls, reducing thrombosis risk.
* Sympatholytic agents These block catecholamines, causing blood vessel dilation and lowered blood pressure. Beta-blockers are useful for treating hypertension, arrhythmias, and angina.
* ACE inhibitors These relax arteries and promote renal excretion of salt and water by inhibiting the activity of angiotensin-converting enzyme.6 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How do cardiovascular drugs help control blood pressure?
Cardiovascular drugs help control blood pressure through various mechanisms. Some drugs, such as vasodilators, relax the smooth muscle in blood vessel walls, widening arteries and reducing resistance to blood flow. Diuretics lower blood pressure by reducing body fluids, while beta-blockers ease the heart's pumping action and widen blood vessels by blocking the effects of epinephrine. ACE inhibitors prevent the formation of angiotensin II, a potent vasoconstrictor, while angiotensin receptor antagonists block angiotensin II binding. Calcium channel blockers promote vasodilation and reduce vascular resistance by slowing calcium ions into smooth muscle cells.
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What side effects can cardiovascular drugs cause?
Cardiovascular drugs impact the heart and blood vessels and are commonly used to treat conditions like hypertension, angina pectoris, heart failure, and arrhythmias.
Many antihypertensive drugs can cause unwanted side effects such as drowsiness, dizziness, impotence, and allergic reactions. Statins, used to lower cholesterol, may cause muscle pain and fatigue, and in rare cases, myopathy (muscle degeneration). Beta-blockers can cause constriction of bronchial smooth muscle, which can be dangerous for people with asthma, and constriction of blood vessels, possibly leading to cold hands and feet.
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How do doctors choose which cardiovascular drug is best for a patient?
Doctors choose cardiovascular drugs based on how they affect the heart and blood vessels, considering the patient's specific cardiovascular issues such as hypertension, angina pectoris, heart failure, and arrhythmias. The drugs are classified by their action on heart rate, the force of heart muscle contraction, or the regularity of the heartbeat. Some drugs act on blood vessels, causing them to constrict to raise blood pressure or relax to lower it. When a patient has an adverse reaction to a drug, doctors can use these classifications to find a drug with similar efficacy but a different structure or mechanism.
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cardiovascular drug, any agent that affects the function of the heart and blood vessels. Drugs that act on the cardiovascular system are among the most widely used in medicine. Examples of disorders in which such drugs may be useful include hypertension (high blood pressure), angina pectoris (chest pain resulting from inadequate blood flow through the coronary arteries to the heart muscle), heart failure (inadequate output of the heart muscle in relation to the needs of the rest of the body), and arrhythmias (disturbances of cardiac rhythm).
Effects on heart function
Drugs affect the function of the heart in three main ways. They can affect the force of contraction of the heart muscle (inotropic effects); they can affect the frequency of the heartbeat, or heart rate (chronotropic effects); or they can affect the regularity of the heartbeat (rhythmic effects).
Contractions
Inotropic agents are drugs that influence the force of contraction of cardiac muscle and thereby affect cardiac output. Drugs have a positive inotropic effect if they increase the force of the heart’s contraction. The cardiac glycosides, substances that occur in the leaves of the foxglove (Digitalis purpurea) and other plants, are the most important group of inotropic agents. Although they have been used for many purposes throughout history, the effectiveness of cardiac glycosides in heart disease was established in 1785 by English physician William Withering, who successfully used an extract of foxglove leaves to treat heart failure. The two compounds most often used therapeutically are digoxin and digitoxin.
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Cardiac glycosides, however, have disadvantageous side effects. These include a tendency to block conduction of the electrical impulse that causes contraction as it passes from the atria to the ventricles of the heart (heart block). Cardiac glycosides also have a tendency to produce an abnormal cardiac rhythm by causing electrical impulses to be generated at points in the heart other than the normal pacemaker region, the cells that rhythmically maintain the heartbeat. These irregular impulses result in ectopic heartbeats, which are out of sequence with the normal cardiac rhythm. Occasional ectopic beats are harmless, but if this process continues to a complete disorganization of the cardiac rhythm (ventricular fibrillation), the pumping action of the heart is stopped, and death occurs within minutes unless resuscitation is performed. Because the margin of safety between the therapeutic and the toxic doses of glycosides is relatively narrow, they must be used carefully.
Cardiac glycosides are believed to increase the force of cardiac muscle contraction by binding to and inhibiting the action of a membrane enzyme that extrudes sodium ions from the cell interior. These drugs also enhance the release of calcium from internal stores, resulting in a rise in intracellular calcium. This subsequently increases the force of contraction, since intracellular calcium ions are responsible for initiating the shortening of muscle cells.
The disturbances of rhythm that may be caused by cardiac glycosides result partly from the depolarization and partly from the increase in intracellular calcium. Because these rhythm disturbances are caused by the same underlying mechanism that causes the beneficial effect, there is no likelihood of finding a cardiac glycoside with a significantly better margin of safety. Apart from their cardiac actions, these glycosides tend to cause nausea and loss of appetite. Because digoxin and digitoxin have long plasma half-lives (two and seven days, respectively), they are liable to accumulate in the body. Treatment with either of these drugs must involve careful monitoring to avoid the adverse effects that may result from their slow buildup in the body.
The second type of inotropic agents that increase the force of cardiac muscle contraction includes dobutamine. Administered intravenously in moderate doses, dobutamine will increase contractility without affecting blood pressure or heart rate.
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