Cardiac Glycoside Plant Poisoning Medication

Categories of drugs used to manage cardiac glycoside plant toxicity include drugs to minimize absorption and increase excretion, drugs that lower extracellular potassium, antidysrhythmics, and antidotes (eg, digoxin Fab fragments).

Class Summary

Activated charcoal is used to bind toxin within the GI tract. Due to enterohepatic/enteroenteric recirculation of cardiac glycosides, multiple doses can be given to help enhance elimination.

Activated charcoal (Liqui-Char)

Emergency treatment in poisoning caused by drugs and chemicals. Network of pores present in activated charcoal adsorbs 100-1000 mg of drug per gram of charcoal. Does not dissolve in water.

For maximum effect, administer within 30 min after ingesting poison. First dose may be given with a cathartic (eg, sorbitol); subsequent doses should be given without a cathartic, as often as q2-6h, and should not be given in presence of ileus.

Class Summary

Hyperkalemia usually results from acute overdose and represents redistribution of potassium from intracellular to extracellular compartment; therefore, drugs of choice include agents that promote potassium redistribution from extracellular to intracellular compartments. Avoid calcium, as it may exacerbate effects of cardiac glycosides and may promote rhythm deterioration when used in this context.

Glucose (D50W) and insulin (Humulin R, Novolin R)

Redistributes potassium intracellularly; onset of action is 30 min and duration of action is 4-6h.

Used for life-threatening hyperkalemia (>6.5 mEq/L). Use cautiously with digoxin Fab as profound hypokalemia may occur.

Observe serum glucose level and administer additional D50W if needed

Sodium bicarbonate (Neut)

Sodium counteracts potassium effects, while alkalosis created by bicarbonate leads to a redistribution of potassium intracellularly. Onset of action is 5-10 min and duration of action is 1-2 h.

Used for life-threatening hyperkalemia (>6.5 mEq/L). Use cautiously with digoxin Fab as profound hypokalemia may occur.

Class Summary

Used to treat variety of bradydysrhythmias and tachydysrhythmias occurring with cardiac glycoside toxicity.

Atropine IV/IM (Atropisol)

Used for bradycardia and conduction blocks in standard ACLS doses.

Doses < 0.1 mg in children or 0.5 mg in adults may lead to paradoxical bradycardia.

Phenytoin (Dilantin)

Useful for ventricular dysrhythmias, such as V-fib, V-tach, and PVCs. DOC for cardiac glycoside-induced tachydysrhythmias. Only antidysrhythmic which stabilizes myocardium and improves conduction through AV node.

Monitor serum phenytoin levels closely to assure therapeutic levels of 10-20 mcg/mL.

Lidocaine (Xylocaine)

Class IB antiarrhythmic that increases electrical stimulation threshold of the ventricle, suppressing automaticity of conduction through the tissue.

Magnesium sulfate

Nutritional supplement in hyperalimentation; cofactor in enzyme systems involved in neurochemical transmission and muscular excitability.

In adults, 60-180 mEq of potassium, 10-30 mEq of magnesium, and 10-40 mmol/L of phosphate per day may be necessary for optimum metabolic response.

Although serum magnesium levels may be normal, existence of intracellular hypomagnesemia has been hypothesized; therefore, magnesium may be beneficial.

Class Summary

Sheep-derived IgG antibodies to digoxin have been used successfully in patients with oleander toxicity. They cross-react with other cardiac glycosides and may be helpful in certain situations, including hyperkalemia not quickly responsive to standard treatments, life-threatening dysrhythmias not quickly responsive to standard treatments, and cardiac arrest.

Digoxin Fab fragments (Digibind)

Because serum digoxin/digitoxin levels do not reflect ingested amount of plant cardiac glycoside, drug levels should not be used to calculate Fab dose. Elevated levels of digoxin or digitoxin only confirm exposure. Undetectable level of serum cardiac glycosides does not rule out exposure. Elevated serum potassium would be a useful indicator when considering this agent.