Atenolol
Encyclopedia
Atenolol is a selective β1 receptor antagonist
, a drug
belonging to the group of beta blocker
s (sometimes written β-blockers), a class of drugs used primarily in cardiovascular disease
s. Introduced in 1976, atenolol was developed as a replacement for propranolol in the treatment of hypertension
. The chemical works by slowing down the heart and reducing its workload. Unlike propranolol, atenolol does not pass through the blood-brain barrier thus avoiding various central nervous system
side effects.
Atenolol is one of the most widely used β-blockers in the United Kingdom
and was once the first-line treatment for hypertension. The role for β-blockers in hypertension was downgraded in June 2006 in the United Kingdom to fourth-line, as they perform less appropriately or effectively than newer drugs, particularly in the elderly. Some evidence suggests that even in normal doses the most frequently used β-blockers carry an unacceptable risk of provoking type 2 diabetes
.
, angina
, acute myocardial infarction, supraventricular tachycardia
, ventricular tachycardia
, congestive heart failure
, prevention of migraine headaches, and the symptoms of alcohol withdrawal.
It is also used to treat the symptoms of Graves Disease, until antithyroid medication can take effect.
Due to its hydrophilic properties, the drug is less suitable in migraine
prophylaxis compared to propranolol, because, for this indication, atenolol would have to reach the brain in high concentrations, which is not the case.
in co-tenidone
) and/or a vasodilator (hydralazine
, or in severe cases minoxidil
). Central alpha-agonists (e.g. clonidine
), ACE Inhibitor
s or Angiotensin II receptor antagonist
s such as losartan
can also be given additionally. Exert caution with calcium-antagonists of the verapamil
-type (non-Dihydropyridine, see also Diltiazem
) as adjunct therapy because of additional negative impact on the muscular strength of the heart. Use of calcium-antagonists of the nifedipine
-type is controversial.
Caution: patients with preexisting bronchial asthma
Caution: only if clearly needed during pregnancy
, as atenolol may retard fetal growth and possibly cause other abnormalities.
It was the main β-blocker identified as carrying a higher risk of provoking type 2 diabetes
, leading to its downgrading in the United Kingdom in June 2006 to fourth-line agent in the management of hypertension.
In addition, β-blockers blunt the usual sympathetic nervous system response to hypoglycemia (i.e. sweating, agitation, tachycardia). These drugs therefore have an ability to mask a dangerously low blood sugar, which further decreases their safety and utility in diabetic patients.
Side effects include:
These side effects may or may not be experienced, but if they are, you should notify your doctor.
More serious side effects can include:
Serious side effects may require urgent medical attention. Some of these side effects are rare and others (not mentioned in the above list) can occur in some people.
Provisional data suggests that antihypertensive therapy with atenolol provides weaker protective action against cardiovascular complications (e.g. myocardial infarction and stroke
) compared to other antihypertensive drugs. In some cases, diuretic
s are superior. However, controlled studies are lacking.
Unlike most other commonly-used β-blockers, atenolol is excreted almost exclusively by the kidney
s. This makes it attractive for use in individuals with end-stage liver
disease.
, severe hypotension
with shock, acute heart failure, hypoglycemia
and bronchospastic reactions. Treatment is largely symptomatic. Hospitalization and intensive monitoring is indicated. In early cases emesis can be induced. Activated charcoal is useful to absorb the drug. Atropine
will counteract bradycardia, glucagon
helps with hypoglycemia, dobutamine
can be given against hypotension and the inhalation of a β2-mimetic as hexoprenalin or salbutamol
will terminate bronchospasms. Blood or plasma atenolol concentrations may be measured to confirm a diagnosis of poisoning in hospitalized patients or to assist in a medicolegal death investigation. Plasma levels are usually less than 3 mg/L during therapeutic administration, but can range from 3–30 mg/L in overdose victims.
Receptor antagonist
A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
, a drug
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...
belonging to the group of beta blocker
Beta blocker
Beta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...
s (sometimes written β-blockers), a class of drugs used primarily in cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
s. Introduced in 1976, atenolol was developed as a replacement for propranolol in the treatment of hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
. The chemical works by slowing down the heart and reducing its workload. Unlike propranolol, atenolol does not pass through the blood-brain barrier thus avoiding various central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
side effects.
Atenolol is one of the most widely used β-blockers in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
and was once the first-line treatment for hypertension. The role for β-blockers in hypertension was downgraded in June 2006 in the United Kingdom to fourth-line, as they perform less appropriately or effectively than newer drugs, particularly in the elderly. Some evidence suggests that even in normal doses the most frequently used β-blockers carry an unacceptable risk of provoking type 2 diabetes
Diabetes mellitus type 2
Diabetes mellitus type 2formerly non-insulin-dependent diabetes mellitus or adult-onset diabetesis a metabolic disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. Diabetes is often initially managed by increasing exercise and...
.
Medical uses
Atenolol is used for a number of conditions including: hypertensionHypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
, angina
Angina
Angina pectoris, commonly known as angina, is chest pain due to ischemia of the heart muscle, generally due to obstruction or spasm of the coronary arteries . Coronary artery disease, the main cause of angina, is due to atherosclerosis of the cardiac arteries...
, acute myocardial infarction, supraventricular tachycardia
Supraventricular tachycardia
Supraventricular tachycardia is a general term that refers to any rapid heart rhythm originating above the ventricular tissue. Supraventricular tachycardias can be contrasted to the potentially more dangerous ventricular tachycardias - rapid rhythms that originate within the ventricular...
, ventricular tachycardia
Ventricular tachycardia
Ventricular tachycardia is a tachycardia, or fast heart rhythm, that originates in one of the ventricles of the heart...
, congestive heart failure
Congestive heart failure
Heart failure often called congestive heart failure is generally defined as the inability of the heart to supply sufficient blood flow to meet the needs of the body. Heart failure can cause a number of symptoms including shortness of breath, leg swelling, and exercise intolerance. The condition...
, prevention of migraine headaches, and the symptoms of alcohol withdrawal.
It is also used to treat the symptoms of Graves Disease, until antithyroid medication can take effect.
Due to its hydrophilic properties, the drug is less suitable in migraine
Migraine
Migraine is a chronic neurological disorder characterized by moderate to severe headaches, and nausea...
prophylaxis compared to propranolol, because, for this indication, atenolol would have to reach the brain in high concentrations, which is not the case.
Hypertension
If atenolol alone fails to control arterial hypertension, the drug can be combined with a diuretic (e.g. with chlortalidoneChlortalidone
Chlortalidone or chlorthalidone is a diuretic drug used to treat hypertension, originally marketed as Hygroton in the USA. It is described as a thiazide diuretic...
in co-tenidone
Co-tenidone
Co-tenidone is a non-proprietary name used to denote a combination of atenolol and chlortalidone. Co-tenidone is used in the treatment of hypertension...
) and/or a vasodilator (hydralazine
Hydralazine
Hydralazine is a direct-acting smooth muscle relaxant used to treat hypertension by acting as a vasodilator primarily in arteries and arterioles...
, or in severe cases minoxidil
Minoxidil
Minoxidil is an antihypertensive vasodilator medication which also slows or stops hair loss and promotes hair regrowth. Now off-patent, it is available over-the-counter for the treatment of androgenic alopecia. Minoxidil must be used indefinitely for continued support of existing hair follicles and...
). Central alpha-agonists (e.g. clonidine
Clonidine
Clonidine is a sympatholytic medication used to treat medical conditions, such as high blood pressure, some pain conditions, ADHD and anxiety/panic disorder...
), ACE Inhibitor
ACE inhibitor
ACE inhibitors or angiotensin-converting enzyme inhibitors are a group of drugs used primarily for the treatment of hypertension and congestive heart failure...
s or Angiotensin II receptor antagonist
Angiotensin II receptor antagonist
Angiotensin II receptor antagonists, also known as angiotensin receptor blockers , AT1-receptor antagonists or sartans, are a group of pharmaceuticals which modulate the renin-angiotensin-aldosterone system...
s such as losartan
Losartan
Losartan is an angiotensin II receptor antagonist drug used mainly to treat high blood pressure . Losartan was the first angiotensin II receptor antagonist to be marketed. Losartan potassium is marketed by Merck & Co. Inc. under the trade name Cozaar...
can also be given additionally. Exert caution with calcium-antagonists of the verapamil
Verapamil
Verapamil is an L-type calcium channel blocker of the phenylalkylamine class. It has been used in the treatment of hypertension, angina pectoris, cardiac arrhythmia, and most recently, cluster headaches. It is also an effective preventive medication for migraine...
-type (non-Dihydropyridine, see also Diltiazem
Diltiazem
Diltiazem is a non-dihydropyridine member of the class of drugs known as calcium channel blockers, used in the treatment of hypertension, angina pectoris, and some types of arrhythmia....
) as adjunct therapy because of additional negative impact on the muscular strength of the heart. Use of calcium-antagonists of the nifedipine
Nifedipine
Nifedipine is a dihydropyridine calcium channel blocker...
-type is controversial.
Contraindications
- bradycardiaBradycardiaBradycardia , in the context of adult medicine, is the resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min. It may cause cardiac arrest in some patients, because those with bradycardia may not be pumping enough oxygen to their heart...
(pulse less than 50 bpm) - cardiogenic shockCardiogenic shockCardiogenic shock is based upon an inadequate circulation of blood due to primary failure of the ventricles of the heart to function effectively....
- asthmaAsthmaAsthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
(may cause broncho-constriction), although unlikely as atenolol is cardioselective - symptomatic hypotension (blood pressure of less than 90/60 mm Hg with dizziness, vertigo etc.)
- angina of the PrinzmetalPrinzmetal's anginaPrinzmetal angina, also known as variant angina or angina inversa, is a syndrome typically consisting of angina at rest that occurs in cycles...
type (vasospastic angina) - metabolic acidosisMetabolic acidosisIn medicine, metabolic acidosis is a condition that occurs when the body produces too much acid or when the kidneys are not removing enough acid from the body. If unchecked, metabolic acidosis leads to acidemia, i.e., blood pH is low due to increased production of hydrogen by the body or the...
(a severe condition with a more acidic blood than normal) - severe disorders in peripheral arterial circulation
- AV-Blockage of second and third degree (a particular form of arrhythmia)
- acutely decompensated congestive heart failure (symptoms may be fluid retention with peripheral edemaEdemaEdema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...
and/or abdominal fluid retention (ascites), and/or lung edema) - sick sinus syndromeSick sinus syndromeSick sinus syndrome, also called sinus node dysfunction, is a group of abnormal heart rhythms presumably caused by a malfunction of the sinus node, the heart's primary pacemaker...
(a particular form of arrhythmia) - hypersensitivity and/or allergyAllergyAn Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
to atenolol - pheochromocytomaPheochromocytomaA pheochromocytoma or phaeochromocytoma is a neuroendocrine tumor of the medulla of the adrenal glands , or extra-adrenal chromaffin tissue that failed to involute after birth and secretes excessive amounts of catecholamines, usually noradrenaline , and adrenaline to a lesser extent...
(a rare type of tumor of the adrenal glands)
Caution: patients with preexisting bronchial asthma
Caution: only if clearly needed during pregnancy
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
, as atenolol may retard fetal growth and possibly cause other abnormalities.
Side effects
Atenolol causes significantly fewer central nervous system side effects (depression, nightmares) and fewer bronchospastic reactions, both due to its particular pharmacologic profile.It was the main β-blocker identified as carrying a higher risk of provoking type 2 diabetes
Diabetes mellitus type 2
Diabetes mellitus type 2formerly non-insulin-dependent diabetes mellitus or adult-onset diabetesis a metabolic disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. Diabetes is often initially managed by increasing exercise and...
, leading to its downgrading in the United Kingdom in June 2006 to fourth-line agent in the management of hypertension.
In addition, β-blockers blunt the usual sympathetic nervous system response to hypoglycemia (i.e. sweating, agitation, tachycardia). These drugs therefore have an ability to mask a dangerously low blood sugar, which further decreases their safety and utility in diabetic patients.
Side effects include:
- indigestion, constipationConstipationConstipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...
- dry mouth
- dizziness or faintness (especially cases of orthostatic hypotensionOrthostatic hypotensionOrthostatic hypotension, also known as postural hypotension, orthostasis, and colloquially as head rush or dizzy spell, is a form of hypotension in which a person's blood pressure suddenly falls when the person stands up or stretches. The decrease is typically greater than 20/10 mm Hg, and may be...
) - cold extremities
- hair loss
- impotence
- rhinitisRhinitisRhinitis , commonly known as a stuffy nose, is the medical term describing irritation and inflammation of some internal areas of the nose. The primary symptom of rhinitis is nasal dripping. It is caused by chronic or acute inflammation of the mucous membrane of the nose due to viruses, bacteria or...
- depression
- confusion
- insomnia, nightmares
- fatigue, weakness or lack of energy
These side effects may or may not be experienced, but if they are, you should notify your doctor.
More serious side effects can include:
- hallucinations
- low blood pressure (hypotensionHypotensionIn physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...
) - skin reactions, e.g. rashRashA rash is a change of the skin which affects its color, appearance or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracked or blistered, swell and may be painful. The causes, and...
, hives, flaking of skin, worsening of psoriasisPsoriasisPsoriasis is an autoimmune disease that appears on the skin. It occurs when the immune system mistakes the skin cells as a pathogen, and sends out faulty signals that speed up the growth cycle of skin cells. Psoriasis is not contagious. However, psoriasis has been linked to an increased risk of... - sensation of 'pins and needlesPins and NeedlesPins and Needles is a musical revue with a book by Arthur Arent, Marc Blitzstein, Emmanuel Eisenberg, Charles Friedman, David Gregory, Joseph Schrank, Arnold B. Horwitt, John Latouche, and Harold Rome and music and lyrics by Rome...
' hands or feet - irritated eyes, visual disturbances
- difficulty hearing
- difficulty speaking
- unsteadiness when walking
Serious side effects may require urgent medical attention. Some of these side effects are rare and others (not mentioned in the above list) can occur in some people.
Asthma
Atenolol is classified as a β1-selective (or 'cardioselective') drug, one that exerts greater blocking activity on myocardial β1-receptors than on β2 receptors in the lung. The β2 receptors are responsible for keeping the bronchial system open. If these receptors are blocked, bronchospasm with serious lack of oxygen in the body can result. However, due to its cardioselective properties, the risk of bronchospastic reactions if using atenolol is reduced compared to nonselective drugs as propranolol. Nonetheless, this reaction may also be encountered with atenolol at high doses. Although traditionally B-blockers have been contraindicated when a person carries a diagnosis of asthma, recent studies have revealed that at moderate doses selective B blockers such as Atenolol are well tolerated.Provisional data suggests that antihypertensive therapy with atenolol provides weaker protective action against cardiovascular complications (e.g. myocardial infarction and stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
) compared to other antihypertensive drugs. In some cases, diuretic
Diuretic
A diuretic provides a means of forced diuresis which elevates the rate of urination. There are several categories of diuretics. All diuretics increase the excretion of water from bodies, although each class does so in a distinct way.- Medical uses :...
s are superior. However, controlled studies are lacking.
Unlike most other commonly-used β-blockers, atenolol is excreted almost exclusively by the kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s. This makes it attractive for use in individuals with end-stage liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
disease.
Overdose
Symptoms of overdose are due to excessive pharmacodynamic actions on β1 and also β2-receptors. These include bradycardiaBradycardia
Bradycardia , in the context of adult medicine, is the resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min. It may cause cardiac arrest in some patients, because those with bradycardia may not be pumping enough oxygen to their heart...
, severe hypotension
Hypotension
In physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...
with shock, acute heart failure, hypoglycemia
Hypoglycemia
Hypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...
and bronchospastic reactions. Treatment is largely symptomatic. Hospitalization and intensive monitoring is indicated. In early cases emesis can be induced. Activated charcoal is useful to absorb the drug. Atropine
Atropine
Atropine is a naturally occurring tropane alkaloid extracted from deadly nightshade , Jimson weed , mandrake and other plants of the family Solanaceae. It is a secondary metabolite of these plants and serves as a drug with a wide variety of effects...
will counteract bradycardia, glucagon
Glucagon
Glucagon, a hormone secreted by the pancreas, raises blood glucose levels. Its effect is opposite that of insulin, which lowers blood glucose levels. The pancreas releases glucagon when blood sugar levels fall too low. Glucagon causes the liver to convert stored glycogen into glucose, which is...
helps with hypoglycemia, dobutamine
Dobutamine
Dobutamine is a sympathomimetic drug used in the treatment of heart failure and cardiogenic shock. Its primary mechanism is direct stimulation of β1 receptors of the sympathetic nervous system. Dobutamine was developed by a laboratory led by Drs...
can be given against hypotension and the inhalation of a β2-mimetic as hexoprenalin or salbutamol
Salbutamol
Salbutamol or albuterol is a short-acting β2-adrenergic receptor agonist used for the relief of bronchospasm in conditions such as asthma and chronic obstructive pulmonary disease. It is marketed as Ventolin among other brand names....
will terminate bronchospasms. Blood or plasma atenolol concentrations may be measured to confirm a diagnosis of poisoning in hospitalized patients or to assist in a medicolegal death investigation. Plasma levels are usually less than 3 mg/L during therapeutic administration, but can range from 3–30 mg/L in overdose victims.
Pregnancy
FDA pregnancy category D. This medication can cause harm to an unborn baby. Do not use atenolol if you are pregnant. Tell your doctor if you become pregnant during treatment. Use an effective form of birth control while you are using this medication. Atenolol can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.Pharmacokinetic data
- tcmax = 2 to 4 hours after oral dosing (time elapsed before maximal concentration in the blood plasmaBlood plasmaBlood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
is reached) - The mean elimination halflife is 6 hours. However, the action of the usual oral dose of 25 to 100 mg lasts over a period of 24 hours.
- Atenolol is a hydrophilic drug. The concentration found in brain tissue is approximately 15% of the plasma concentration only. The drug crosses the placentaPlacentaThe placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...
barrier freely. In the milk of breastfeedingBreastfeedingBreastfeeding is the feeding of an infant or young child with breast milk directly from female human breasts rather than from a baby bottle or other container. Babies have a sucking reflex that enables them to suck and swallow milk. It is recommended that mothers breastfeed for six months or...
mothers, approximately 3 times the plasma concentrations are measured. - Atenolol is almost exclusively eliminated renallyKidneyThe kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
and is well removable by dialysisDialysisIn medicine, dialysis is a process for removing waste and excess water from the blood, and is primarily used to provide an artificial replacement for lost kidney function in people with renal failure...
. A compromised liverLiverThe liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
function does not lead to higher peak-activity and/or a longer halflife with possible accumulation.
Popular Culture
- Atenolol has been referenced as the gateway drugGateway drugThe gateway drug theory is the hypothesis that the use of less deleterious drugs may lead to a future risk of using more dangerous hard drugs and/or crime...
for treating hypertension. It is the most widely prescribed drug for this use but patients do not often remain on it because of the side effects it carries.
External links
- Atenolol U.S. National Library of Medicine: Drug Information Portal