30 Questions
What is the primary therapeutic use of Digitalis glycosides?
Treatment of congestive heart failure
What is the toxic effect of Digitalis lanata?
Poisonous effect
Which condition does Digitalis glycosides protect against during certain atrial arrhythmias?
Ventricular fibrillation
What is the recommended therapeutic serum concentration of digoxin?
1.2-1.7 ng/mL
What percentage of patients taking a digitalis preparation may experience toxicity?
20-30%
Which factor is NOT associated with an increased risk of digoxin toxicity?
Hyperkalemia
What are the early manifestations of digoxin intoxication?
Gastrointestinal disturbances and blurred vision
What is the reported mortality rate with a toxic dose of digoxin?
Up to 25%
What is the most appropriate treatment for severe acute digitalis toxicity?
Atropine administration
What is the recommended timing for activated charcoal administration in case of digitalis ingestion?
Within 6-8 hours after ingestion
Which intervention is likely more appropriate for chronic digitalis toxicity in patients with renal insufficiency?
Cholestyramine administration
What is the crucial factor for effective management of digitalis toxicity?
Continuous hemodynamic assessment
What is not recommended for treating chronic toxicity in patients with renal failure?
Forced diuresis
What should be considered if gastric lavage is performed in chronic toxicity in patients with renal failure?
Atropine
What is recommended for correcting dysrhythmias in chronic toxicity in patients with renal failure?
Sodium bicarbonate and insulin plus glucose
When may hemodialysis be necessary in chronic toxicity in patients with renal failure?
In uncontrolled hyperkalemia
What is the first-line treatment for significant dysrhythmias due to digitalis toxicity?
Digoxin immune Fab (Digibind)
What should be corrected to reduce cardiac sensitivity to digoxin?
Hypokalemia
What can act as a temporizing antiarrhythmic agent until Fab fragments are available?
Magnesium
What must be reconstituted with sterile water for IV injection?
Digoxin immune Fab (Digibind)
What is the typical response time observed after infusion of digoxin Fab fragments?
Within 20-30 minutes
In which patients is initially administering half doses of digoxin Fab fragments considered the best approach?
Patients with chronic toxicity
What is the elimination half-life of the drug-antibody complex of digoxin Fab fragments?
About 16 hours
What is the recommended treatment for hemodynamically stable patients with bradyarrhythmias and supraventricular arrhythmias?
Observation, supportive care, discontinuation of the drug, proper hydration, and GI binding agents
What is the recommended therapeutic goal for magnesium sulfate in digoxin-toxic patients with dysrhythmias?
A magnesium level between 4 and 5 mEq/L
What is the role of atropine in managing severe sinus bradycardia induced by digoxin?
Useful in reversing severe sinus bradycardia induced by digoxin and in blocking its effects on the sinoatrial and AV nodes
What is the recommended approach for managing premature ventricular contractions (PVCs) in digoxin-toxic patients?
Observation, unless the patient is hemodynamically unstable, in which case lidocaine may be effective
What is the effect of phenytoin on digitalis-induced tachydysrhythmias?
Suppresses digitalis-induced tachydysrhythmias without diminishing the contractile effects
Which medication is contraindicated in the management of digoxin toxicity due to its potential to increase digoxin levels?
Calcium channel blockers
What is the recommended initial bolus dose of lidocaine according to advanced cardiac life support (ACLS) guidelines?
100 mg
Study Notes
Management of Digoxin Toxicity
- Short-acting beta blockers, such as esmolol, can be used for supraventricular tachyarrhythmias with rapid ventricular rates, but they may precipitate advanced or complete atrioventricular block in patients with sinoatrial or AV node depression.
- Calcium channel blockers are contraindicated in digoxin toxicity as they may increase digoxin levels.
- Premature ventricular contractions (PVCs) may require only observation unless the patient is hemodynamically unstable, in which case lidocaine may be effective.
- Ventricular tachycardia responds best to digoxin immune therapy, but phenytoin and lidocaine are useful if immune therapy is ineffective or unavailable.
- Phenytoin can dissociate the inotropic and dysrhythmic action of digitalis, suppressing digitalis-induced tachydysrhythmias without diminishing the contractile effects.
- Lidocaine may be given in boluses of 100 mg according to advanced cardiac life support (ACLS) guidelines, followed by a maintenance infusion at 1-4 mg/min if successful.
- Phenytoin has been administered in boluses of 100 mg every 5-10 minutes, up to a loading dose of 15 mg/kg.
- Atropine may be useful in reversing severe sinus bradycardia induced by digoxin and in blocking its effects on the sinoatrial and AV nodes.
- Magnesium sulfate, given intravenously, has been shown to terminate dysrhythmias in digoxin-toxic patients with and without overt cardiac disease, with a therapeutic goal of a magnesium level between 4 and 5 mEq/L.
- Quinidine and procainamide are contraindicated in the management of digoxin toxicity.
Test your knowledge of the management of digoxin toxicity with this quiz. Explore the appropriate use of medications such as beta blockers, calcium channel blockers, lidocaine, phenytoin, atropine, and magnesium sulfate in treating various cardiac manifestations of digoxin toxicity.
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