Calcium channel blocker toxicity is the taking of too much of the medications known as calcium channel blockers (CCBs), either by accident or on purpose. This often causes a slow heart rate and

low blood pressure Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dia ...

. This can progress to the heart stopping altogether. Some CCBs can also cause a

fast heart rate Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (su ...

as a result of the low blood pressure. Other symptoms may include nausea, vomiting, sleepiness, and

shortness of breath Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing di ...

. Symptoms usually occur in the first six hours but with some forms of the medication may not start until 24 after hours. There are a number of treatments that may be useful. These include efforts to reduce absorption of the drug including:

activated charcoal "Activated" is a song by English singer Cher Lloyd. It was released on 22 July 2016 through Vixen Records. The song was made available to stream exclusively on ''Rolling Stone'' a day before to release (on 21 July 2016). Background In an inter ...

taken by mouth if given shortly after the ingestion or

whole bowel irrigation Whole bowel irrigation (WBI) is a medical process involving the rapid administration of large volumes of an osmotically balanced macrogol solution (GoLYTELY, CoLyte), either orally or via a nasogastric tube, to flush out the entire gastrointesti ...

if an extended release formula was taken. Efforts to bring about vomiting are not recommended. Medications to treat the toxic effects include: intravenous fluids,

calcium gluconate Calcium gluconate is a mineral supplement and medication. As a medication it is used by injection into a vein to treat low blood calcium, high blood potassium, and magnesium toxicity. Supplementation is generally only required when there is ...

glucagon Glucagon is a peptide hormone, produced by alpha cells of the pancreas. It raises concentration of glucose and fatty acids in the bloodstream, and is considered to be the main catabolic hormone of the body. It is also used as a medication to trea ...

, high dose

insulin Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the ''INS'' gene. It is considered to be the main anabolic hormone of the body. It regulates the metabol ...

vasopressors An antihypotensive agent, also known as a vasopressor agent or simply vasopressor, or pressor, is any substance, whether endogenous or a medication, that tends to raise low blood pressure. Some antihypotensive drugs act as vasoconstrictors to in ...

and lipid emulsion.

Extracorporeal membrane oxygenation Extracorporeal membrane oxygenation (ECMO), also known as extracorporeal life support (ECLS), is an extracorporeal technique of providing prolonged cardiac and respiratory support to persons whose heart and lungs are unable to provide an adequ ...

may also be an option. More than ten thousand cases of calcium channel blocker toxicity were reported in the United States in 2010. Along with

beta blockers Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms, and to protect the heart from a second heart attack after a first heart attack ( secondary prevention). They are a ...

and

digoxin Digoxin (better known as Digitalis), sold under the brand name Lanoxin among others, is a medication used to treat various heart conditions. Most frequently it is used for atrial fibrillation, atrial flutter, and heart failure. Digoxin is on ...

calcium channel blockers have one of the highest rates of death in overdose. These medications first became available in the 1970s and 1980s. They are one of the few types of medication in which one pill can result in the death of a child.

Signs and symptoms

Most people who have taken too much of a calcium channel blocker, especially

diltiazem Diltiazem, sold under the brand name Cardizem among others, is a calcium channel blocker medication used to treat high blood pressure, angina, and certain heart arrhythmias. It may also be used in hyperthyroidism if beta blockers cannot be ...

, get slow heart rate and

(

vasodilatory shock Vasodilatory shock, vasogenic shock, or vasoplegic shock is a medical emergency belonging to shock along with cardiogenic shock, septic shock, allergen-induced shock and hypovolemic shock. When the blood vessels suddenly relax, it results in v ...

). This can progress to the heart stopping altogether. CCBs of the dihydropyridine group, as well as flunarizine, predominantly cause reflex tachycardia as a reaction to the low blood pressure. Other potential symptoms include: nausea and vomiting, a decreased level of consciousness, and breathing difficulties. Symptoms usually begin within 6 hours of taking the medication by mouth. With extended release formulations symptoms may not occur for up to a day.

Seizures An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with los ...

are rare in adults but in children occur more often.

Hypocalcaemia Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mmol ...

may also occur.

Cause

Calcium channel blockers, also known as calcium channel antagonists, are widely used for a number of health conditions. Thus they are commonly present in many people's homes. In young children one pill may cause serious health problems and potentially death. The calcium channel blocker that caused the greatest number of deaths in 2010 in the United States was verapamil. This agent is believed to cause more heart problems than many of the others.

Diagnosis

A blood or urine test to diagnose overdose is not generally available. CCB overdose may cause

high blood sugar Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood sugar level higher than 11.1 mmol/L (200 mg/dL), but symptoms may not start to become noticeable until even ...

levels, and this is often a sign of how severe the problem will become.

Electrocardiogram

CCB toxicity can cause a number of electrocardiogram abnormalities with a low

sinus rhythm A sinus rhythm is any cardiac rhythm in which depolarisation of the cardiac muscle begins at the sinus node. It is characterised by the presence of correctly oriented P waves on the electrocardiogram (ECG). Sinus rhythm is necessary, but not ...

being the most common. Others include:

QT prolongation Long QT syndrome (LQTS) is a condition affecting repolarization (relaxing) of the heart after a heartbeat, giving rise to an abnormally lengthy QT interval. It results in an increased risk of an irregular heartbeat which can result in fainting, ...

bundle branch block A bundle branch block is a defect in one the bundle branches in the electrical conduction system of the heart. Anatomy and physiology The heart's electrical activity begins in the sinoatrial node (the heart's natural pacemaker), which is situat ...

first-degree atrioventricular block First-degree atrioventricular block (AV block) is a disease of the electrical conduction system of the heart in which electrical impulses conduct from the cardiac atria to the ventricles through the atrioventricular node (AV node) more slowly t ...

, and even

sinus tachycardia Sinus tachycardia is an elevated sinus rhythm characterized by an increase in the rate of electrical impulses arising from the sinoatrial node. In adults, sinus tachycardia is defined as a heart rate greater than 100 beats per minute (bpm). Th ...

Differential

It may not be possible to tell the difference between

beta blocker toxicity Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms, and to protect the heart from a second heart attack after a first heart attack ( secondary prevention). They are a ...

and calcium channel blocker overdose based on signs and symptoms.

Management

The medical management of CCB toxicity may be difficult. It may not improve with the usual treatments used for a low blood pressure and a slow heart rate. In those who have no symptoms or signs six hours following taking an immediate release formulation and 24 hours after taking an extended release formulation need no further medical treatment.

Detoxification

Activated charcoal "Activated" is a song by English singer Cher Lloyd. It was released on 22 July 2016 through Vixen Records. The song was made available to stream exclusively on ''Rolling Stone'' a day before to release (on 21 July 2016). Background In an inter ...

is recommended if it can be given within an hour or two of taking the calcium channel blockers. In those who have taken an extended release formulation of a CCB but are otherwise doing fine,

with

polyethylene glycol Polyethylene glycol (PEG; ) is a polyether compound derived from petroleum with many applications, from industrial manufacturing to medicine. PEG is also known as polyethylene oxide (PEO) or polyoxyethylene (POE), depending on its molecular w ...

may be useful. Causing

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteri ...

by the use of medications such as

ipecac Syrup of ipecac (), or simply ipecac, is a drug that was once widely used as an expectorant (in low doses) and a rapid-acting emetic (in higher doses). It is obtained from the dried rhizome and roots of the ipecacuanha plant (''Carapichea ipecac ...

is not recommended.

Insulin

High doses of intravenous

with

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, usi ...

may be useful and are a first line treatment in overdoses. As this treatment may cause a drop in blood sugar and blood potassium levels, these should be monitored closely.

Other

Intravenous

calcium chloride Calcium chloride is an inorganic compound, a salt with the chemical formula . It is a white crystalline solid at room temperature, and it is highly soluble in water. It can be created by neutralising hydrochloric acid with calcium hydroxide. Cal ...

is considered a specific

antidote An antidote is a substance that can counteract a form of poisoning. The term ultimately derives from the Greek term φάρμακον ἀντίδοτον ''(pharmakon) antidoton'', "(medicine) given as a remedy". Antidotes for anticoagulants are s ...

s. Slow heart rate can be treated with

atropine Atropine is a tropane alkaloid and anticholinergic medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate, and to decrease saliva production during surgery. It is typically giv ...

and

sympathomimetic Sympathomimetic drugs (also known as adrenergic drugs and adrenergic amines) are stimulant compounds which mimic the effects of endogenous agonists of the sympathetic nervous system. Examples of sympathomimetic effects include increases in heart ...

s. Low blood pressure is treated with vasopressors such as

adrenaline Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands and ...

. There is tentative clinical evidence and good theoretical evidence of the benefit of lipid emulsion in severe overdoses of CCBs.

Methylene blue Methylthioninium chloride, commonly called methylene blue, is a salt used as a dye and as a medication. Methylene blue is a thiazine dye. As a medication, it is mainly used to treat methemoglobinemia by converting the ferric iron in hemoglob ...

may also be used for those with low blood pressure that does not respond to other treatments.

Epidemiology

More than 10,000 cases of potential calcium channel blocker toxicity occurred in the United States in 2010. When death occurs in medicine overdose, heart medications are the cause more than 10% of time. The three most common types of heart medications that result in this outcome are calcium channel blockers along with beta blockers and

References

External links

* {{Antidotes Poisoning by drugs, medicaments and biological substances Calcium channel blockers Wikipedia medicine articles ready to translate Wikipedia emergency medicine articles ready to translate