Amiodarone is an
antiarrhythmic agentAntiarrhythmic agents are a group of pharmaceuticals that are used to suppress fast rhythms of the heart , such as atrial fibrillation, atrial flutter, ventricular tachycardia, and ventricular fibrillation....
(medication used for irregular heart beat) used for various types of tachyarrhythmias (fast forms of irregular heart beat), both ventricular and supraventricular (atrial) arrhythmias. Discovered in 1961, it was not approved for use in the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
until 1985. Despite relatively common side-effects, it is used in arrhythmias that are otherwise difficult to treat with medication. Related newer compounds, such as
dronedaroneDronedarone is a drug by Sanofi-Aventis, mainly for the indication of cardiac arrhythmias . It was approved by the FDA on July 2, 2009. It is now available as 400 mg tablets in 60 count bottles...
, have lower
efficacyEfficacy is the capacity to produce an effect. It is used to mean different specific things in different fields.- Healthcare :In a healthcare context, efficacy indicates the capacity for beneficial change of a given intervention Efficacy is the capacity to produce an effect. It is used to mean...
but a reduced rate of side-effects.
History
Amiodarone was initially developed in 1961 at the Labaz company,
BelgiumThe Kingdom of Belgium is a country in northwest Europe. It is a founding member of the European Union and hosts its headquarters, as well as those of other major international organizations, including NATO...
, by chemists Tondeur and Binon. It became popular in Europe as a treatment for angina pectoris.
As a doctoral candidate at Oxford University, Dr. Bramah Singh determined that amiodarone and
sotalolSotalol is a drug used in individuals with rhythm disturbances of the heart, and to treat hypertension in some individuals.Sotalol is a non-selective beta blocker...
had antiarrhythmic properties and belonged to a new class of antiarrhythmic agents (what would become the class III antiarrhythmic agents). Today the mechanisms of action of amiodarone and sotalol remain unknown. It is thought to involve prolonging the action potential duration, prolonging the refractory period, or interacting with K+ channels.
Based on Singh's work, the
ArgentinianArgentina, officially the Argentine Republic , is the second largest country in South America, constituted as a federation of 23 provinces and an autonomous city, Buenos Aires. It is the eighth largest country in the world by land area and the largest among Spanish-speaking nations, though Mexico,...
physician Dr. Mauricio Rosenbaum began using amiodarone to treat his patients who suffered from supraventricular and ventricular arrhythmias, with impressive results. Based on papers written by Dr. Rosenbaum developing Singh's theories, physicians in the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
began prescribing amiodarone to their patients with potentially life-threatening arrhythmias in the late 1970s. By 1980, amiodarone was commonly prescribed throughout Europe for the treatment of arrhythmias, but in the U.S. amiodarone remained unapproved by the
Food and Drug AdministrationThe Food and Drug Administration is a Government agency of the United States Department of Health and Human Services and is responsible for regulating and supervising the safety of foods, tobacco products, dietary supplements, Medication drugs, vaccines, Biopharmaceutical, blood transfusion,...
, and physicians were forced to directly obtain amiodarone from pharmaceutical companies in
CanadaCanada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean...
and
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
.
The FDA was reluctant to officially approve the use of amiodarone, since initial reports had shown increased incidence of serious pulmonary side-effects of the drug. In the mid 1980s, the European pharmaceutical companies began putting pressure on the FDA to approve amiodarone by threatening to cut the supply to American physicians if it were not approved. In December 1985, amiodarone was approved by the FDA for the treatment of arrhythmias. This makes amiodarone one of the few drugs approved by the FDA without rigorous randomized clinical trials.
Dosing
Amiodarone is available in oral and intravenous formulations.
Orally, it is available under the trade names
Pacerone (produced by Upsher-Smith Laboratories, Inc.) and
Cordarone (produced by Wyeth-Ayerst Laboratories) in 200mg and 400 mg tablets; It is also available under the trade name
Aratac (produced by Alphapharm Pty Ltd) in 100 mg and 200 mg tablets in Australia and New Zealand. Also
Arycor in South Africa (Produced by Winthrop Pharmaceuticals.) in doses of 100 mg and 200 mg scored tablets. In South America, it is known as
Atlansil and is produced by Roemmers.
It is also available in intravenous ampules and vials, typically in 150 mg increments.
The dose of amiodarone administered is tailored to the individual and the dysrhythmia that is being treated. When administered orally, the
bioavailabilityIn pharmacology, bioavailability is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. By definition, when a medication is administered intravenously, its bioavailability is 100%...
of amiodarone is quite variable. Absorption ranges from 22 to 95%, with better absorption when it is given with food.
Amiodarone is fat-soluble, and tends to concentrate in tissues including fat, muscle, liver, lungs, and skin. This confers a high
volume of distributionThe volume of distribution , also known as apparent volume of distribution, is a pharmacological term used to quantify the distribution of a medication between plasma and the rest of the body after oral or parenteral dosing. It is defined as the volume in which the amount of drug would need to be...
(5000 liters in a 70 kg adult) and a long half-life. Due to the long half-life of amiodarone, oral loading typically takes days to weeks.
An oral loading dose is typically a total of 10 grams, divided over one to two weeks but there are many other dosing regimens. Once an individual is loaded, a typical maintenance dose of amiodarone is 100 or 200 mg either once or twice daily.
An intravenous loading dose is typically 300 mg in 20-30cc D5W for cardiac arrest. The loading infusion for dysrhythmias is typically 150 mg in a 100cc bag of D5W given over 10 minutes. Both can be followed by a 360 mg slow infusion over 6 hours then a maintenance infusion of 540 mg over 18 hours.
Mechanism of action
Amiodarone is categorized as a class III antiarrhythmic agent, and prolongs phase 3 of the
cardiac action potentialThe cardiac action potential is a specialized action potential in the heart, with unique properties necessary for function of the electrical conduction system of the heart.The cardiac action potential differs significantly in different portions of the heart...
. It has numerous other effects however, including actions that are similar to those of antiarrhythmic classes Ia, II, and IV.
Amiodarone shows
beta blockerBeta blockers is a class of drugs used for various indications, but particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction , and hypertension. Propranolol was the first clinically useful beta adrenergic receptor antagonist. Invented by Sir James W...
-like and
potassium channel blockerPotassium channel blockers are agents which interfere with conduction through potassium channels.-Arrhythmia:Potassium channel blockers used in the treatment of cardiac arrhythmia are classified as class III antiarrhythmic agents.-Mechanism:...
-like actions on the SA and AV nodes, increases the refractory period via sodium- and potassium-channel effects, and slows intra-cardiac conduction of the
cardiac action potentialThe cardiac action potential is a specialized action potential in the heart, with unique properties necessary for function of the electrical conduction system of the heart.The cardiac action potential differs significantly in different portions of the heart...
, via sodium-channel effects.
Amiodarone resembles thyroid hormone, and its binding to the nuclear thyroid receptor might contribute to some of its pharmacologic and toxic actions
Indications for use
Because amiodarone has a low incidence of pro-arrhythmic effects, it has been used both in the treatment of acute life-threatening arrhythmias as well as the chronic suppression of arrhythmias. It is useful both in supraventricular arrhythmias and ventricular arrhythmias.
Ventricular fibrillation
The treatment of choice for
ventricular fibrillationVentricular fibrillation is a condition in which there is uncoordinated contraction of the cardiac muscle of the ventricles in the heart, making them tremble rather than contract properly...
(VF) is electrical defibrillation. However, amiodarone can be useful in shock-refractory VF. In the ARREST trial, amiodarone was shown to improve survival to
hospitalA hospital is an institution for health care providing patient treatment by specialized staff and equipment, and often but not always providing for longer-term patient stays....
admission (when compared to
placeboA placebo is a sham medical intervention. In one common placebo procedure, a patient is given an inert sugar pill, told that it may improve his/her condition, but not told that it is in fact inert...
) in individuals who suffer
cardiac arrestA cardiac arrest, also known as cardiopulmonary arrest or circulatory arrest, is the abrupt cessation of normal circulation of the blood due to failure of the heart to contract effectively during systole....
with shock-refractory VF. It is on the basis of this study that the guidelines created by the
American Heart AssociationThe American Heart Association is a non-profit organization in the United States that fosters appropriate cardiac care in an effort to reduce disability and deaths caused by cardiovascular disease and stroke. It is headquartered in Dallas, Texas...
for the treatment of VF include amiodarone as a second line agent (after
epinephrineEpinephrine is a hormone and neurotransmitter that participates in the "fight or flight" response of the sympathetic nervous system...
or
vasopressinArginine vasopressin , also known as vasopressin, argipressin or antidiuretic hormone , is a hormone found in most mammals, including humans. Vasopressin is a peptide hormone. It is derived from a preprohormone precursor that is synthesized in the hypothalamus and stored in vesicles at the...
). ARREST was not adequately powered to demonstrate survival to hospital discharge.
Ventricular tachycardia
Amiodarone may be used in the treatment of ventricular tachycardia in certain instances. Individuals with hemodynamically
unstable ventricular tachycardia
should not initially receive amiodarone. These individuals should be
cardiovertedCardioversion is a medical procedure by which an abnormally fast heart rate or cardiac arrhythmia is converted to a normal rhythm, using electricity or drugs. Synchronized electrical cardioversion uses a therapeutic dose of electric current to the heart, at a specific moment in the cardiac cycle...
out of their unstable rhythm.
Amiodarone can be used in individuals with hemodynamically stable ventricular tachycardia. In these cases, amiodarone can be used regardless of the individual's underlying heart function and the type of ventricular tachycardia; it can be used in individuals with monomorphic ventricular tachycardia as well as individuals with polymorphic ventricular tachycardia. The dose of amiodarone is 150 mg IV administered over 10 minutes.
Atrial fibrillation
Individuals who have undergone
open heart surgeryCoronary artery bypass surgery, also coronary artery bypass graft surgery, and colloquially heart bypass or bypass surgery is a surgical procedure performed to relieve angina and reduce the risk of death from coronary artery disease...
are at an increased risk of developing
atrial fibrillationAtrial fibrillation is the most common cardiac arrhythmia and involves the two upper chambers of the heart. Its name comes from the fibrillating of the heart muscles of the atria, instead of a coordinated contraction...
(or AF) in the first few days post-procedure. In the ARCH trial, intravenous amiodarone (2
gramThe gram , ; symbol g, is a unit of mass.Originally defined as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre, and at the temperature of melting ice" , a gram is now defined as one one-thousandth of the SI base unit, the kilogram, or...
s administered over 2 days) has been shown to reduce the incidence of atrial fibrillation after open heart surgery when compared to placebo. However, clinical studies have failed to demonstrate long-term efficacy and have shown potentially fatal side effects such as pulmonary toxicities. While Amiodarone is not approved for AF by the FDA, it is a commonly prescribed off-label treatment due to the lack of efficacious treatment alternatives.
So called 'acute onset atrial fibrillation', defined by the North American Society of Pacing and Electrophysiology (NASPE)in 2003, responds well to short duration treatment with amiodarone. This has been demonstrated in seventeen randomised controlled trials, of which five included a placebo arm. The incidence of severe side effects in this group is low.
The benefit of amiodarone in the treatment of atrial fibrillation in the critical care population has yet to be determined but it may prove to be the agent of choice where the patient is haemodynamically unstable and unsuitable for DC cardioversion. It is recommended in such a role by the UK government's
National Institute for Health and Clinical ExcellenceThe National Institute for Health and Clinical Excellence or NICE is a special health authority of the National Health Service in England and Wales...
(NICE).
Contraindications
The only absolute contraindications to the administration of amiodarone is allergic reaction (ie:
anaphylaxisAnaphylaxis is an acute systemic and severe type I hypersensitivity allergic reaction in humans and other mammals. The term comes from the Greek words ανα ana and φύλαξις phylaxis . Minute amounts of allergens may cause a life-threatening anaphylactic reaction...
) to the compound. However, because of the wide spectrum of the mechanism of action of amiodarone and the numerous side effects possible, there are a number of groups for which care should be taken when administering the drug.
Individuals who are pregnant or may become pregnant are strongly advised to not take amiodarone. Since amiodarone can be expressed in breast milk, women taking amiodarone are advised to stop nursing.
It is contraindicated in individuals with sinus nodal
bradycardiaBradycardia , as applied to adult medicine, is defined as a resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min....
,
atrioventricularThe atrioventricular node is a part of electrical control system of the heart that co-ordinates heart rate. It electrically connects atrial and ventricular chambers...
block, and second or third degree heart block who do not have an
artificial pacemakerA pacemaker is a medical device which uses electrical impulses, delivered by electrodes contacting the heart muscles, to regulate the beating of the heart...
.
Individuals with baseline depressed lung function should be monitored closely if amiodarone therapy is to be initiated.
The injection should not be given to neonates, because the benzyl alcohol it contains may cause the fatal "gasping syndrome".
Amiodarone can worsen the cardiac arrhythmia brought on by
FoxgloveDigitalis is a genus of about 20 species of herbaceous perennials, shrubs, and biennials that are commonly called foxgloves. The genus was traditionally placed in the figwort family Scrophulariaceae, but upon review of phylogenetic research, it has now been placed in the much enlarged family...
poisoning.
Metabolism
Amiodarone is extensively metabolized in the liver, and can affect the metabolism of numerous other
drugsA pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
. The major metabolite of amiodarone is desethylamiodarone (DEA), which also has antiarrhythmic properties. The metabolism of amiodarone is inhibited by
grapefruitThe grapefruit is a subtropical citrus tree known for its bitter fruit, an 18th-century hybrid first bred in Jamaica. When found in Barbados it was named the "forbidden fruit"; it is also called the "shaddock", after its creator....
juice, leading to elevated
serumBlood plasma is the yellow liquid component of blood, in which the blood cells in whole blood would normally be suspended. It makes up about 55% of the total blood volume. It is mostly water and contains dissolved proteins, glucose, clotting factors, mineral ions, hormones and carbon dioxide...
levels of amiodarone.
On August 8, 2008 FDA issued a warning of the risk of
rhabdomyolysisRhabdomyolysis is the rapid breakdown of skeletal muscle due to injury to muscle tissue. The muscle damage may be caused by physical , chemical, or biological factors...
, which can lead to kidney failure or death, when
simvastatinSimvastatin , is a hypolipidemic drug belonging to the class of pharmaceuticals called "statins". It is used to control hypercholesterolemia and to prevent cardiovascular disease...
is used with amiodarone. This interaction is dose-dependent with simvastatin doses exceeding 20 mg. This drug combination especially with higher doses of simvastatin should be avoided.
Interactions with other drugs
The
pharmacokineticsPharmacokinetics is a branch of pharmacology dedicated to the determination of the fate of substances administered externally to a living organism...
of numerous
drugsA pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
, including many that are commonly administered to individuals with
heartThe heart is a muscular organ found in all vertebrates that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
disease, are affected by amiodarone. Particularly, doses of
digoxinDigoxin , also known as digitalis, is a purified cardiac glycoside extracted from the foxglove plant, Digitalis lanata. Its corresponding aglycone is digoxigenin, and its acetyl derivative is acetyldigoxin...
should be halved in individuals taking amiodarone.
Amiodarone potentiates the action of
warfarinWarfarin is an anticoagulant. It was initially marketed as a pesticide against rats and mice and is still popular for this purpose, although more potent poisons such as brodifacoum have since been developed...
. Individuals taking both of these medications should have their warfarin dose halved and their anticoagulation status (measured as
prothrombin timeThe prothrombin time and its derived measures of prothrombin ratio and international normalized ratio are measures of the extrinsic pathway of coagulation. They are used to determine the clotting tendency of blood, in the measure of warfarin dosage, liver damage, and vitamin K status...
(PT) and international normalized ratio (INR)) measured more frequently. The effect of amiodarone in the warfarin concentration can be as early as a few days after initiation of treatment, or can be delayed a few weeks.
Amiodarone inhibits the action of the cytochrome P450
isozymeIsozymes are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. These enzymes usually display different kinetic parameters Isozymes (also known as isoenzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. These enzymes...
family. This reduces the clearance of many drugs, including the following: -
- Cyclosporine
- Digoxin
Digoxin , also known as digitalis, is a purified cardiac glycoside extracted from the foxglove plant, Digitalis lanata. Its corresponding aglycone is digoxigenin, and its acetyl derivative is acetyldigoxin...
- Flecainide
Flecainide acetate is a class Ic antiarrhythmic agent used to prevent and treat tachyarrhythmias...
- Procainamide
Procainamide is a pharmaceutical antiarrhythmic agent used for the medical treatment of cardiac arrhythmias, classified by the Vaughan Williams classification system as class Ia.-Mechanism:...
- Quinidine
Quinidine is a pharmaceutical agent that acts as a class I antiarrhythmic agent in the heart. It is a stereoisomer of quinine, originally derived from the bark of the cinchona tree.-Mechanism:...
- Sildenafil
Sildenafil citrate, sold as Viagra, Revatio and under various other trade names, is a drug used to treat erectile dysfunction and pulmonary arterial hypertension . It was developed and is being marketed by the pharmaceutical company Pfizer. It acts by inhibiting cGMP specific phosphodiesterase type...
- Simvastatin
Simvastatin , is a hypolipidemic drug belonging to the class of pharmaceuticals called "statins". It is used to control hypercholesterolemia and to prevent cardiovascular disease...
- Theophylline
Theophylline, also known as dimethylxanthine, is a methylxanthine drug used in therapy for respiratory diseases such as COPD or asthma under a variety of brand names. Due to its numerous side-effects, these drugs are now rarely administered for clinical use. As a member of the xanthine family, it...
- Warfarin
Warfarin is an anticoagulant. It was initially marketed as a pesticide against rats and mice and is still popular for this purpose, although more potent poisons such as brodifacoum have since been developed...
Excretion
Unlike most other
drugsA pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
, which are excreted via the
urineUrine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra. Cellular metabolism generates numerous waste compounds, many rich in nitrogen, that require elimination from the bloodstream...
, excretion is primarily hepatic and biliary with almost no elimination via the renal route and it is not dialyzable [Package Insert- Pacerone(R)]. Elimination half-life average of 58 days (ranging from 25-100 days [Remington: The Science and Practice of Pharmacy 21st edition]) for amiodarone and 36 days for the active metabolite, desethylamiodarone (DEA) [Package Insert- Pacerone(R)]. There is 10-50% transfer of amiodarone and DEA in the placenta as well as presence in breast milk [Package Insert- Pacerone(R)]. Accumulation of amiodarone and DEA occurs in adipose tissue and highly perfused organs (ie. liver, lungs) [Package Insert- Pacerone(R)], therefore, if an individual was taking amiodarone on a chronic basis, if it is stopped it will remain in the system for weeks to months.
Side effects
Amiodarone has numerous side effects. Most individuals administered amiodarone on a chronic basis will experience at least one side effect.
Lung
The most serious reaction that is due to amiodarone is interstitial lung disease. Risk factors include high cumulative dose, more than 400 milligrams per day, duration over two months, increased age, and preexisting pulmonary disease. Some individuals were noted to develop pulmonary fibrosis after a week of treatment, while others did not develop it after years of continuous use. Common practice is to avoid the agent if possible in individuals with decreased lung function.
The most specific test of pulmonary toxicity due to amiodarone is a dramatically decreased
DLCODLCO stands for the diffusing capacity of the lung for carbon monoxide, the test used to determine this parameter. DLCO is the extent to which oxygen passes from the air sacs of the lungs into the blood...
noted on pulmonary function testing.
Thyroid
Due to the iodine content of the agent (37.3% by weight), abnormalities in
thyroidThe thyroid is one of the largest endocrine glands in the body. This gland is found in the neck inferior to the thyroid cartilage and at approximately the same level as the cricoid cartilage...
function are common. Amiodarone is structurally similar to
thyroxineThyroxine, or 3,5,3',5'-tetraiodothyronine , a form of thyroid hormones is the major hormone secreted by the follicular cells of the thyroid gland. Thyroxine is synthesized via the iodination and covalent bonding of the phenyl portions of tyrosine residues found in an initial peptide,...
(a thyroid hormone), which contributes to the effects of amiodarone on thyroid function. Both under- and overactivity of the thyroid may occur on amiodarone treatment. Measurement of free
thyroxineThyroxine, or 3,5,3',5'-tetraiodothyronine , a form of thyroid hormones is the major hormone secreted by the follicular cells of the thyroid gland. Thyroxine is synthesized via the iodination and covalent bonding of the phenyl portions of tyrosine residues found in an initial peptide,...
(FT4) alone may be unreliable in detecting these problems and
thyroid-stimulating hormoneThyroid-stimulating hormone is a peptide hormone synthesized and secreted by thyrotrope cells in the anterior pituitary gland which regulates the endocrine function of the thyroid gland....
(TSH) should therefore also be checked every 6 months.
- Hypothyroidism
Hypothyroidism is the disease state in humans and in animals caused by insufficient production of thyroid hormone by the thyroid gland. Cretinism is a form of hypothyroidism found in infants.-Causes:...
(slowing of the thyroid, called the Wolff-Chaikoff effectWolff–Chaikoff effect is used to describe hypothyroidism caused by ingestion of a large amount of iodine.It is an autoregulatory phenomenon which inhibits formation of thyroid hormones inside of the thyroid follicle. This becomes evident secondary to elevated levels of circulating iodide...
) occurs frequently; in the SAFE trial, which compared amiodarone with other medications for the treatment of atrial fibrillation, biochemical hypothyroidism (as defined by a TSH level of 4.5-10 mU/l) occurred in 25.8% of the amiodarone-treated group as opposed to 6.6% of the control group (taking placebo or sotalolSotalol is a drug used in individuals with rhythm disturbances of the heart, and to treat hypertension in some individuals.Sotalol is a non-selective beta blocker...
). Overt hypothyrodism (defined as TSH >10 mU/l) occurred at 5.0% compared to 0.3%; most of these (>90%) were detected within the first six months of amiodarone treatment.
- Hyperthyroidism
Hyperthyroidism is the term for overactive tissue within the thyroid gland,resulting in overproduction and thus an excess of circulating free thyroid hormones: thyroxine , triiodothyronine , or both...
(an overactive thyroid, called the JodbasedowJod-Basedow effect is used to describe hyperthyroidism following administration of iodine or iodide, either as a dietary supplement or as contrast medium....
effect) can also occur. However, in the SAFE trial, the increased rate of hyperthyroidism (5.3% compared to 2.4%) was not statistically significant. Most hyperthyroid patients (defined as TSH <0.35 mU/l) were asymptomatic.
Thyroid uptake measurements (I-123 or I-131), which are used to differentiate causes of hyperthyroidism, are generally unreliable in patients who have been taking amiodarone. Because of the high iodine content of amiodarone, the thyroid gland is effectively saturated, thus preventing further uptake of isotopes of iodine. However, the radioactive iodine uptake (nuclear thyroid uptake test) may still be helpful in the diagnosis and management of amiodarone-induced hyperthyroidism.
Eye
CorneaThe cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is approximately 43...
l micro-deposits (Corneal verticillata, also called vortex keratopathy) are almost universally present (over 90%) in individuals taking amiodarone for at least 6 months. These deposits typically do not cause any symptoms. About 1 in 10 individuals may complain of a bluish halo.
Optic neuropathy occurs in 1-2% of people and is not dosage dependent. Bilateral optic disk swelling and mild and reversible visual field defects can also occur.
Gastrointestinal system and liver
Abnormal liver enzyme results are common in patients on amiodarone. Much rarer are
jaundiceJaundice, also known as icterus , is a yellowish discoloration of the skin, the conjunctival membranes over the sclerae , and other mucous membranes caused by hyperbilirubinemia...
,
hepatomegalyHepatomegaly is the condition of having an enlarged liver. It is a nonspecific medical sign having many causes, which can broadly be broken down into infection, direct toxicity, hepatic tumours, or metabolic disorder. Often, hepatomegaly will present as an abdominal mass...
(liver enlargement), and
hepatitisHepatitis implies injury to the liver characterized by the presence of inflammatory cells in the tissue of the organ. The name is from ancient Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...
(inflammation of the liver).
Low-dose amiodarone has been reported to cause pseudo-alcoholic cirrhosis.
Skin
Long-term administration of amiodarone is associated with a blue-grey discoloration of the skin. This is more commonly seen in individuals with lighter skin tones. The discoloration may revert upon cessation of the drug. However, the skin color may not return completely to normal.
Individuals taking amiodarone may become more sensitive to the harmful effects of
UV-AUltraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than x-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
light. Using sunblock that also blocks UV-A rays appears to prevent this side effect.
See also
- Advanced cardiac life support
Advanced cardiac life support or refers to a set of clinical interventions for the urgent treatment of cardiac arrest and other life threatening medical emergencies, as well as the knowledge and skills to deploy those interventions....
(ACLS)
- Antiarrhythmic agents
- Atrial fibrillation
Atrial fibrillation is the most common cardiac arrhythmia and involves the two upper chambers of the heart. Its name comes from the fibrillating of the heart muscles of the atria, instead of a coordinated contraction...
- Cardiac action potential
The cardiac action potential is a specialized action potential in the heart, with unique properties necessary for function of the electrical conduction system of the heart.The cardiac action potential differs significantly in different portions of the heart...
- Dronedarone
Dronedarone is a drug by Sanofi-Aventis, mainly for the indication of cardiac arrhythmias . It was approved by the FDA on July 2, 2009. It is now available as 400 mg tablets in 60 count bottles...
(similar drug under investigation)
- Ventricular tachycardia
Ventricular tachycardia is a tachycardia, or fast heart rhythm, that originates in one of the ventricles of the heart...
External links