What are the toxic effects of cardiac glycosides?

What are the toxic effects of cardiac glycosides?

The predominant features of acute poisoning include gastrointestinal symptoms (nausea, vomiting, abdominal pain, diarrhoea), hyperkalaemia, generalized weakness, drowsiness and, importantly, cardiotoxicity (bradycardia and heart block, dysrhythmias). These may appear within a few hours of acute poisoning.

What type of effect do glycosides have on the heart?

Cardiac glycosides are a class of organic compounds that increase the output force of the heart and increase its rate of contractions by acting on the cellular sodium-potassium ATPase pump. They are selective steroidal glycosides and are important drugs for the treatment of heart failure and cardiac rhythm disorders.

How does digoxin cause toxicity?

Pathophysiology – Digoxin Toxicity Digoxin toxicity causes hyperkalemia, or high potassium. The sodium/potassium ATPase pump normally causes sodium to leave cells and potassium to enter cells. Blocking this mechanism results in higher serum potassium levels.

Are glycosides harmful?

Exposure to cyanide from unintentional or intentional consumption of cyanogenic glycosides may lead to acute intoxications, characterized by growth retardation and neurological symptoms resulting from tissue damage in the central nervous system (CNS).

What is the effect of digitalis on heart rate?

Digitalis produces an increase of blood flow, a decrease of vascular resistance, venodilation, and a decrease of central venous pressure and heart rate (Figure 1). The vasodilation is the result of an increase in cardiac output and direct baroreflex-mediated withdrawal of sympathetic vasoconstriction.

Do cardiac glycosides decrease heart rate?

Digitalis compounds, such as digoxin, are useful for reducing ventricular rate when it is being driven by a high atrial rate. The mechanism of this beneficial effect of digoxin is its ability to activate vagal efferent nerves to the heart (parasympathomimetic effect).

What is digoxin toxicity symptoms?

What are the symptoms of digoxin toxicity?

• Lack of appetite, nausea, vomiting, or diarrhea.
• Headache, confusion, anxiety, or hallucinations.
• Restlessness, weakness, or depression.
• Changes in vision such as blurred vision or seeing halos around bright objects.

What is the toxic level of digoxin?

Therapeutic levels of digoxin are 0.8-2.0 ng/mL. The toxic level is >2.4 ng/mL.

What causes cardiovascular toxicity?

What is cardiac toxicity? Cardiac (heart) toxicity is a side effect of cancer treatment that leads to damage to the heart muscle or valves. Both chemotherapy and radiation can contribute to cardiac toxicity, depending on the type of medication(s) used and where radiation treatment was given.

What is the difference between toxic and?

Poisonous and toxic essentially refer to any substance or action that will cause you or anything else harm. These terms are often used interchangeably. 2. Toxic has a broader definition whereas poisonous usually refers to only biological agents.

What do cardiac glycosides do?

Cardiac glycosides are medicines for treating heart failure and certain irregular heartbeats. They are one of several classes of drugs used to treat the heart and related conditions.

What are symptoms of digoxin toxicity?

Some early warning signs of overdose are confusion, loss of appetite, nausea, vomiting, diarrhea, or vision problems. Other signs of overdose are changes in the rate or rhythm of the heartbeat (becoming irregular or slow), palpitations (feeling of pounding in the chest), or fainting.

What does a cardiac glycoside do?

Cardiac glycosides are medicines for treating heart failure and certain irregular heartbeats. They are one of several classes of drugs used to treat the heart and related conditions. These medicines are a common cause of poisoning.

What do you give for digoxin toxicity?

Digoxin-specific antibody antigen-binding fragments (DSFab), brand name Digibind or Digifab, are an effective antidote that directly binds digoxin. DSFab is indicated for life-threatening toxicity including: Ventricular arrhythmias. High-grade heart blocks.

How does digoxin toxicity cause hyperkalemia?

(1) Digoxin inhibits the cardiac Na/K antiporter (orange oval, above). This causes an increase in intracellular sodium and a decrease in intracellular potassium. The decrease in intracellular potassium is what causes hyperkalemia in patients with digoxin overdose.

What is the toxicity of cardiac glycosides?

Thus, though cardiac glycosides have been used for their medicinal function, their toxicity must also be recognized. For example, in 2008 US poison centers reported 2,632 cases of digoxin toxicity, and 17 cases of digoxin-related deaths.

What is the relationship between potassium and cardiotoxicity in glycoside toxicity?

Hyperkalaemia is a manifestation of cardiac glycoside poisoning, and although a higher potassium concentration is associated with increased risk, the relationship between potassium concentration and cardiotoxicity is poorly defined. In acute digoxin exposures, when present, hyperkalaemia is a hallmark of poisoning 23.

What is the function of cardiac glycosides in the heart?

The refractory period of the AV node is increased, so cardiac glycosides also function to decrease heart rate. For example, the ingestion of digoxin leads to increased cardiac output and decreased heart rate without significant changes in blood pressure; this quality allows it to be widely used medicinally in the treatment of cardiac arrhythmias.

What are the treatment options for cardiac glycoside toxicity?

Therapeutic options to treat cardiac glycoside toxicity include pharmacological antagonists of bradycardia, reversal of Na+‐K+‐ATPase inhibition or enhanced elimination of the cardiac glycoside.