Digitalis intoxication

Review: Failure of current digoxin monitoring for toxicity: new monitoring recommendations to maintain therapeutic levels for efficacy

The current recommendations for monitoring digoxin, a narrow therapeutic index drug, are limited to confirming medication use or investigating suspicion of toxicity and fail our oath to do no harm. Numerous meta-analyses evaluating digoxin use consistently recommend frequent monitoring to maintain the level of 0.5 to ≤1.0 ng/ml because higher levels lead to increased morbidity and mortality without benefit. Data from the United States National Poison Control Center (2012-2020) show annual deaths due to digoxin of 18-36 compared to lithium's 1-7, and warfarin's 0-2 respectively. The latter drugs also have narrow therapeutic indexes like digoxin yet are more carefully monitored. Recognition of digoxin toxicity is impaired as levels are not being routinely checked after medications are added to a patient's regimen. In addition, providers may be using ranges to guide treatment that are no longer appropriate. It is imperative that monitoring guidelines and laboratory therapeutic levels are revised to reduce morbidity and mortality due to digoxin. In this review, we provide a comprehensive literature review of digoxin monitoring guidelines, digoxin toxicity, and evidence to support revising the ranges for serum digoxin monitoring.

Deleterious cardiovascular effect of exosome in digitalis-treated decompensated congestive heart failure

Heart failure (HF) is a medical condition inability of the heart to pump sufficient blood to meet the metabolic demand of the body to take place. The number of hospitalized patients with cardiovascular diseases is estimated to be more than 1 million each year, of which 80% to 90% of patients ultimately progress to decompensated HF. Digitalis glycosides exert modest inotropic actions when administered to patients with decompensated HF. Although its efficacy in patients with HF and atrial fibrillation is clear, its value in patients with HF and sinus rhythm has often been questioned. A series of recent studies have cast serious doubt on the benefit of digoxin when added to contemporary HF treatment. We are hypothesizing the role and mechanism of exosome and its biological constituents responsible for worsening the disease state and mortality in decompensated HF patients on digitalis.

Digoxin therapy in the elderly: pharmacokinetic considerations in nursing

Digoxin is effective in controlling ventricular rhythm in atrial fibrillation and is used in heart failure when angiotensin converting enzyme inhibitors and diuretics are ineffective. Because use of more than 1 drug is often required with these conditions, pharmacokinetic considerations, including those related to complementary medicine, are important. Increased awareness of drug action in the elderly is important because there is often an increase in body fat and leaner muscle mass as well as changes in organ function, such as that of the kidney, which alters drug activity. Nurses have an important role to play in the safe administration of digoxin.

Cost-effectiveness analysis of the use of digoxin immune Fab (ovine) for treatment of digoxin toxicity

Each year many people have digitalis toxicity severe enough to require extensive hospital treatment. Digoxin immune Fab[ovine]-Fab fragments (Digibind) have been shown to reverse digitalis toxicity and substantially reduce the risk of death. Data were used from uncontrolled studies of patients treated with Fab fragments as well as clinical, medical care and pharmacokinetic data from symptomatically treated patients to derive estimates of the difference in clinical outcomes and medical care costs when treating with this new drug. Estimates are derived separately for treatment of patients with toxicity that is immediately life-threatening and patients whose manifestations are not immediately life-threatening. Treatment with Fab fragments reduces the probability of dying more for the seriously toxic than for the less seriously toxic patient. Such treatment is generally associated with an increase in total medical care costs for the seriously toxic patients because more of them survive the toxic episode and require additional medical care before discharge from the hospital. For these patients, the estimated cost per life-year saved is between $1,900 and $5,400. When Fab fragments are used to treat less seriously toxic patients, total medical care costs decrease because of an estimated decreased number of days in the coronary care unit and decreased use of pacemakers and other aggressive treatments.

Treatment of a case of lanatoside C intoxication with digoxin-specific F(ab')2 antibody fragments

In animal experiments arrhythmias induced by cardiac glycosides which prove fatal if untreated can be terminated by administration of glycoside-specific antibodies. Immunotherapy with digoxin-specific antibody fragments had hitherto only been employed on one occasion, namely in a person who had taken a massive overdose of digoxin with suicidal intent and who had failed to respond to symptomatic treatment. The present paper describes the use of F(ab')2 fragments of digoxin-specific antibodies in a female patient with lanatoside C intoxication to treat the associated life-threatening cardiac arrhythmia. The arrhythmia was rapidly terminated and normal sinus rhythm was restored. Treatment with the heterologous antibodies did not cause any side-effects.

[Plasma concentrations of digoxin in patients under intensive care conditions and in patients undergoing anesthesia and operation (author' transl)]

Pharmacokinetic behavior of digoxin or beta-acetyldigoxin was examined in 66 patients (27 patiets under intensive care conditions, partially with controlled breathing, 22 patients undergoing extirpation of the uterus and 17 patients treated with radium or chemotherapeutics; 19 males and 47 females) by determining plasma concentrations of digoxin (PDC). After intravenous and oral application with a maintenance dose of 0.20--0.50 mg/day blood was taken daily during a 2 to 3 week period, resulting in 510 determinations. 24 hours after the first application of 0.50 mg digoxin i.v. the mean values of PDC amounted to 0.62 +/- 0.08 ng/ml. After 0.40 or 0.25 mg digoxin per day i.v. therapeutical concentrations could be observed at the third vs fifth day. An equilibrium of PDC was reached on the 6th day after starting digitalization using maintenance doses. Intravenous application of 0.25, 0.40 or 0.50 mg digoxin per day resulted in a mean steady state of 0.68 +/- 0.37, 0.86 +/- 0.33 or 1.27 +/- 0.49 ng/ml PDC, respectively. The results were significantly different (p less than 0.01--0.001). Serial measurements indicated a great variation of PDC. In patients without renal failure the intraindividual variation of the plasma concentrations was maximal 37.4% referring to the mean steady state, interindividual 37.1% and the evaluation of the inter- and intraindividual differences amounted to 54.1%. After oral administration of digoxin (maintenance dose: 0.50 mg/day) or beta-acetyldigoxin (maintenance doses: 0.20--0.40 mg/day) differences in PDC of 38.3% and 29.7% were obtained. Body weight, age and serum creatinine concentration were partly responsible for the variance of PDC. Multiple linear regression between stead state PDC and dose, age, body weight and serum creatinine concentration revealed 62.1% of the variance of the PDC after intravenous administration of digoxin. After oral administration of beta-acetyldigoxin 39.9% were obtained. Thus, 40% of the variance were caused by differences in distribution and elimination of digoxin after i.v. application. After oral application additional 20% of the variance could be attributed to resorption and possible disturbances.