Antidigoxin Antibodies

The antidigitoxin or the antidigoxin antibodies (Digibind) have been used to control digitalis intoxication. The antibody mobilizes depot digoxin and is excreted by the kidney as an anti-body-digoxin complex. 

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Dasgupta A, Szele-Stevens KA. Neutralization of free digoxin-like immunor-eactive components of oriental medicines Dan Shen and Lu-Shen-Wan by the Fab fragment of antidigoxin antibody (Digibind). Am J Clin Pathol 2004 121 276-281. 

Hyperkalemia carries a poor prognosis and is usually an indication for antidigoxin antibody. The suggestion that intravenous calcium should be used to treat the hjrper-kalemia that can occur in digitalis intoxication (173) has been challenged, on the grounds that it can increase the risk of cardiac dysrhythmias in such cases (174). 

In a systematic review of 250 publications no controlled, randomized trials were found, and the authors concluded that there was little or no scientific evidence of efficacy, because there are no randomized, controlled trials (179). However, this is one case in which the cumulative anecdotal evidence is overwhelmingly convincing, and there can be no doubt that antidigoxin antibodies are highly effective in the treatment of digoxin intoxication and of intoxication with other cardiac glycosides. The important question is whether there are cases in which the antibodies need not be used, and guidelines have yet to be developed. 

Overdose of digoxin in a neonate caused complete atrioventricular block and cardiogenic shock, which were completely reversed within 4 hours after administration of the first dose of antidigoxin antibody a second dose was given 48 hours later, when first-degree atrioventricular block occurred (180). 

Plasma exchange has been used to enhance the rate of removal of antidigoxin antibody Fab fragments in a... 

Table 3 Methods for calculating the required dose of antidigoxin antibody fragments in cases of digoxin or digitoxin intoxication...

Plasma exchange was used to enhance the rate of removal of antidigoxin antibody Fab fragments in a 46-year-old man with renal insufficiency (190). Removal of the digoxin-Fab complexes in this case prevented their subsequent dissociation and a further increase in the unbound concentration of digoxin. 

The authors proposed that plasma exchange is best used in these cases within the first 3 hours after the administration of antidigoxin antibodies. 

Digoxin toxicity occurred in a neonate who was also given erythromycin (274). She had bradycardia and coupled extra beats. Digoxin and erythromycin were withdrawn and she was given antidigoxin antibodies. Her plasma digoxin concentration, which had previously been 1.8 ng/ml, had risen to 8.0 ng/ml. 

Spironolactone can alter the results of some digoxin radioimmunoassays, because it and its metabohtes, such as canrenone and 7-alpha-thiomethylspironolactone, are immunoreactive with some forms of antidigoxin antibody (29-31). This results in an overestimate of the true digoxin concentration, because the assay reads the interfering substances as digoxin. 

A similar procedure was used for antidigoxin antibody assay. Digoxin-benzo crown ether conjugates, rather than cortisol were entrapped in the PVC membrane of the K+ sensitive electrode. The detection limit was in the range of a few g/ml. The sensor was regenerated by a brief (<60 s) immersion in glycine-HCl buffer, pH 2.8. The membrane was stable for 1-2 weeks under conditions of routine use. 

Digoxin Sinus bradycardia AV block TVagal tone Antidigoxin antibodies Temporary pacing Atrial tachycardia may also be present... 

Digoxin Atrial tachycardia with AV block ventricular bigeminy and others DAD-related triggered activity (+T vagal tone) Antidigoxin antibodies Coexistence of abnormal impulses with abnormal sinus or AV nodal function... 

Untreated, oleander seed poisoning carries a mortality of 10% in Sri Lanka and treatment of yellow oleander poisoning is limited to the use of repeated doses of activated charcoal and atropine [17 antidigoxin antibodies are not available for routine use because of the high cost. Based on an animal study and on a small phase II study in patients with yellow oleander poisoning, a double-blind, randomized, placebo-controlled trial has been set up to assess the effectiveness of fructose-l,6-diphosphate (FDP) in acute yellow oleander poisoning [18 ]. Eligible patients will be randomized to either FDP or an equal amount of isotonic saline. The primary outcome measure will be sustained reversion to sinus rhythm at a rate of over 50/minute within 2 hours. Secondary outcomes will include death, reversal of hyperkalaemia at 6, 12, 18, and 24 hours, and maintenance of sinus rhythm. 

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