Introduction
Digoxin toxicity will cause adverse health effects. It may occur due to accidental ingestion or consumption of large doses of Digoxin for therapeutic purposes. Digoxin toxicity mainly results in cardiac complications. Acute toxicity will cause nausea, discomfort, irritability, and vomiting. Digoxin-specific antibody fragments (Digoxin immune fab) are used as antidotes to reduce Digoxin toxicity and adverse effects. They are administered based on the levels of Digoxin present in the body.
What Is Digoxin Toxicity?
Digoxin is a drug used to treat various cardiovascular diseases. Its toxicity can occur due to accidental ingestion of a large amount of Digoxin or chronic use of Digoxin for therapeutic purposes in large amounts. Some people may develop low tolerance to Digoxin due to underlying medical conditions and develops toxicity. Diuretic drugs (for removing excess fluid from the body) are usually given to patients with heart diseases. These drugs remove excess fluids present in the body and cause low levels of potassium in the body (hypokalemia). Low potassium levels in the body increase the risk of Digoxin toxicity. Magnesium levels can also increase the toxicity of Digoxin in our bodies. Low magnesium levels are associated with patients consuming Digoxin for heart diseases. Certain drugs like Verapamil, Amiodarone, Quinidine, and Flecainide interact with Digoxin and cause toxicity.
What Are the Signs of Digoxin Toxicity?
Cardiac toxicity is the most important effect of Digoxin overdose. Acute toxicity will cause symptoms like vomiting, vertigo, and nausea. Chronic toxicity results in nonspecific symptoms. Common signs and symptoms associated with Digoxin toxicity are the following:
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Vomiting.
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Confusion.
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Fast heartbeat.
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Blurred vision (yellow vision).
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Irregular pulse.
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Decreased urine output.
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Loss of appetite.
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Overall sweating.
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Difficulty in breathing.
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Decreased consciousness.
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Heart block (AV block).
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Ventricular tachycardia (fast heart rate).
What Are the Treatment Options for Digoxin Toxicity?
Emergency medical care must be given to patients with Digoxin toxicity. Symptoms associated with acute Digoxin toxicity, like vomiting, breathlessness, diarrhea, and irregular heart rate, must be managed immediately. Drugs like Phenytoin, magnesium, and Lidocaine can be used for toxicity management. Phenytoin and Lidocaine will help to reduce ventricular automaticity induced by Digoxin. Ventricular arrhythmia induced by Digoxin toxicity can be suppressed using magnesium. The most effective and important treatment option available for Digoxin toxicity is a Digoxin-specific antibody (Digoxin immune fab). They are highly effective in reducing life-threatening complications associated with Digoxin toxicity.
What Are the Indications for the Use of Digoxin-Specific Antibody Fragments?
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Acute ingestion of more than 10 milligrams of Digoxin in healthy adults.
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Acute ingestion of more than four milligrams of Digoxin in children.
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A serum Digoxin concentration of more than ten nanograms per milliliter.
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Severe gastrointestinal problems.
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Potassium concentration of more than five millimoles per liter (hyperkalemia).
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Symptoms of organ dysfunction.
What Is the Dosing Regimen for Digoxin-Specific Antibody Fragments?
Digoxin-specific antibody fragments (Digoxin immune fab) are used as antidotes to treat the symptoms of acute Digoxin ingestion and toxicity due to chronic therapy. They are antibodies obtained from anti-Digoxin antibodies cultured in sheep. The dose of Digoxin-specific antibody fragments is determined based on the amount of Digoxin to be neutralized.
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Dose for Acute Ingestion of Digoxin - 760 milligrams or 20 vials of Digoxin-specific antibody (Digoxin immune fab) is given to treat life-threatening Digoxin toxicity in children and adults. During administration in children, volume overload is monitored thoroughly. Large doses of Digoxin-specific antibodies have a fast onset of action but may cause febrile reactions. Ten vials of Digoxin-specific antibody fragments will be administered initially, and after watching the body response, the next ten vials will be given if needed.
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Dose for Chronic Toxicity of Digoxin - Six vials or 228 milligrams for chronic toxicity are adequate to reduce toxicity and symptoms. Small doses of one vial are usually sufficient in small children and infants.
How Is Digoxin-Specific Antibody Dosage Calculated?
The amount of Digoxin-specific antibody (Digoxin fab) administered is calculated based on two different methods. The first one is based on the Digoxin levels ingested, and the other one is based on the weight of the person and serum Digoxin concentration.
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Acute Toxicity With Unknown Levels - One vial of Digoxin-specific antibody (Digoxin immune fab) contains 38 milligrams of Digoxin-specific Fab fragments that will bind to 0.5 milligrams of Digoxin. Thus we can calculate the total number of vials required for the patient by dividing the total Digoxin body load in milligrams by 0.5 milligrams per vial. In acute toxicity, the total body load of Digoxin in milligrams will be approximately equal to the amount of Digoxin tablets ingested in milligrams. It is calculated by multiplying the Digoxin dose ingested by 0.8, which is the bioavailability of Digoxin.
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Known Digoxin Concentration - When the Digoxin concentration is known, Digoxin-specific antibody concentration is calculated by using the product of drug concentration and weight in kilograms divided by 100.
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Ingested Amount and Serum Digoxin Level Unknown - In this situation, ten vials of Digoxin-specific antibody fragments (Digoxin immune fab) are given to the patient, and a clinical response is observed. Further doses are added to the patient depending on the clinical condition. Five vials are given initially for small children with less than 20 kilograms of weight.
What Are the Side Effects of Using Digoxin-Specific Antibodies?
The use of Digoxin-specific antibodies may cause side effects in some people. Proper allergic history must be taken before administration.
Side effects include the following:
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Itching.
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Cough.
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Skin redness.
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Short of breath.
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Swelling of tongue, face, and lips.
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Wheezing.
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Increased urination.
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Muscle weakness.
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Increased thirst.
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Irregular heartbeats.
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Joint pain.
Conclusion
Digoxin-specific antibody fragments (Digoxin immune fab) are the widely accepted treatment option for Digoxin toxicity. It is relatively safe for the majority of patients. Digoxin-specific antibody fragments will help to save patients from a life-threatening arrhythmia caused by Digoxin toxicity. The dose of Digoxin-specific antibody fragments administered to each patient is calculated based on the Digoxin level ingested, the weight of the patient, and serum Digoxin levels.
