Pharmacological treatment of cardiac glycoside poisoning

Cardiac glycosides are an important cause of poisoning, reflecting their widespread clinical usage and presence in natural sources. Poisoning can manifest as varying degrees of toxicity. Predominant clinical features include gastrointestinal signs, bradycardia and heart block. Death occurs from ventricular fibrillation or tachycardia. A wide range of treatments have been used, the more common including activated charcoal, atropine, β-adrenoceptor agonists, temporary pacing, anti-digoxin Fab and magnesium, and more novel agents include fructose-1,6-diphosphate (clinical trial in progress) and anticalin. However, even in the case of those treatments that have been in use for decades, there is debate regarding their efficacy, the indications and dosage that optimizes outcomes. This contributes to variability in use across the world. Another factor influencing usage is access. Barriers to access include the requirement for transfer to a specialized centre (for example, to receive temporary pacing) or financial resources (for example, anti-digoxin Fab in resource poor countries). Recent data suggest that existing methods for calculating the dose of anti-digoxin Fab in digoxin poisoning overstate the dose required, and that its efficacy may be minimal in patients with chronic digoxin poisoning. Cheaper and effective medicines are required, in particular for the treatment of yellow oleander poisoning which is problematic in resource poor countries.

[Repeated unexplained cardiac glycoside poisoning]

One of the major tasks of psychiatry, suicide risk assessment, is supposed to reduce morbidity and mortality. However, assessing suicide risk can be quite challenging because it depends almost entirely upon subjective clinical judgment. The patient is often ambivalent towards committing suicide and may conceal his or her real intentions. Therefore, identification of suicidal intention may be daunting even after thorough, repeated psychiatric evaluations. Hence, clinicians must always maintain a high level of doubt, and act accordingly. In the following report we describe the case of a young man who acted out several concealed and very severe suicide attempts that put his Life at risk. Lacking any apparent risk factors, and due to prolonged efforts to cover up his actions, true evaluation and exposure of suicidal risk was extremely difficult. This case study is reported with the goal of emphasizing the complexity of suicide assessment and the need to frequently re-examine one's findings.

Effect of administration of activated charcoal and fibre on absorption, excretion and steady state blood levels of digoxin and digitoxin. Evidence for intestinal secretion of the glycosides

The effects of activated charcoal and fibre on absorption and stationary plasma levels of digoxin and digitoxin have been studied. The effect of fibre alone is small but an interactive effect on absorption may occur if fibre and digoxin are ingested simultaneously. Charcoal effectively decreases glycoside absorption even when administered after the glycosides. During maintenance therapy with digoxin or digitoxin, charcoal administration decreased the glycoside plasma levels by 31.2% and 18.3% respectively. It is suggested that even digoxin may have a significant biliary excretion and enterohepatic circulation or that this glycoside has a significant intestinal secretion. The therapeutic implication of this study is that charcoal may be of value, not only in the management of acute glycoside poisoning, but also in some cases of more chronic intoxication.

Antidotes for acute cardenolide (cardiac glycoside) poisoning

BACKGROUND

Cardenolides are naturally occurring plant toxins which act primarily on the heart. While poisoning with the digitalis cardenolides (digoxin and digitoxin) are reported worldwide, cardiotoxicity from other cardenolides such as the yellow oleander are also a major problem, with tens of thousands of cases of poisoning each year in South Asia. Because cardenolides from these plants are structurally similar, acute poisonings are managed using similar treatments. The benefit of these treatments is of interest, particularly in the context of cost since most poisonings occur in developing countries where resources are very limited.

OBJECTIVES

To determine the efficacy of antidotes for the treatment of acute cardenolide poisoning, in particular atropine, isoprenaline (isoproterenol), multiple-dose activated charcoal (MDAC), fructose-1,6-diphosphate, sodium bicarbonate, magnesium, phenytoin and anti-digoxin Fab antitoxin.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, the Controlled Trials Register of the Cochrane Collaboration, Current Awareness in Clinical Toxicology, Info Trac, www.google.com.au, and Science Citation Index of studies identified by the previous searches. We manually searched the bibliographies of identified articles and personally contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials where antidotes were administered to patients with acute symptomatic cardenolide poisoning were identified.

DATA COLLECTION AND ANALYSIS

We independently extracted data on study design, including the method of randomisation, participant characteristics, type of intervention and outcomes from each study. We independently assessed methodological quality of the included studies. A pooled analysis was not appropriate.

MAIN RESULTS

Two randomised controlled trials were identified, both were conducted in patients with yellow oleander poisoning. One trial investigated the effect of MDAC on mortality, the relative risk (RR) was 0.31 (95% confidence interval (CI) 0.12 to 0.83) indicating a beneficial effect. The second study found a beneficial effect of anti-digoxin Fab antitoxin on the presence of cardiac dysrhythmias at two hours post-administration; the RR was 0.60 (95% CI 0.44 to 0.81). Other benefits were also noted in both studies and serious adverse effects were minimal. Studies assessing the effect of antidotes on other cardenolides were not identified. One ongoing study investigating the activated charcoal for acute yellow oleander self-poisoning was also identified.

AUTHORS' CONCLUSIONS

There is some evidence to suggest that MDAC and anti-digoxin Fab antitoxin may be effective treatments for yellow oleander poisoning. However, the efficacy and indications of these interventions for the treatment of acute digitalis poisoning is uncertain due to the lack of good quality controlled clinical trials. Given pharmacokinetic differences between individual cardenolides, the effect of antidotes administered to patients with yellow oleander poisoning cannot be readily translated to those of other cardenolides. Unfortunately cost limits the use of antidotes such as anti-digoxin Fab antitoxin in developing countries where cardenolide poisonings are frequent. More research is required using relatively cheap antidotes which may also be effective.

Successful treatment of oleander intoxication (cardiac glycosides) with digoxin-specific Fab antibody fragments in a 7-year-old child

A 7-year-old girl presented six hours after ingestion of a yellow oleander seed (Thevetia peruviana) with severe emesis, change in colour vision and complete heart block. Initial treatment with phenytoin and isoprenalin infusion led to intermittent supraventricular and ventricular tachycardia. The patient was then treated with two intravenous doses of 190 mg of digoxin-specific Fab antibody fragments (Digibind). Subsequently the patient's rhythm reverted to sinus rhythm and the symptoms resolved within 2 hours.

CONCLUSION

administration of digoxin-specific Fab antibody fragments in an otherwise healthy child after oleander intoxication is safe and without adverse reactions.

The role of fluorescence polarization immuno-assay in the diagnosis of plant-induced cardiac glycoside poisoning livestock in South Africa

Poisoning with cardiac glycoside-containing plants is collectively the most important plant-associated poisoning of livestock in southern Africa. As a diagnosis of this significant poisoning is currently based on circumstantial evidence, a practical chemical procedure indicating the presence of cardiac glycosides in plants and animal specimens would be of considerable benefit. The fluorescence polarization immunoassay (FPIA) method, used to determine digoxin plasma levels in humans and dogs, was adapted to estimate cardiac glycoside levels in known cardiac-glycoside- containing plants as well as in the rumen and organs of dosed sheep. Positive FPIA values were obtained with bufadienolide-containing plants, while negative results were obtained with plants not known to contain cardiac glycosides. The FPIA has aided in the diagnosis of cardiac glycoside poisoning in livestock and game in 30 outbreaks examined at the Division of Toxicology, Onderstepoort Veterinary Institute. Each outbreak is briefly described. As a result of this assay, a better understanding of cardiac glycoside poisoning has been reached.

[Cardiotoxic plants]

In statistics from Poison Information Center in Kraków plant poisonings comprise 2% of the total registered poisonings. In toxicology cardiac glycosides poisonings existing in common foxglove plant, lilies of the valley, oleander are essential. Species of cardiotoxic plants which may cause a danger in Poland are presented in the research. The toxic mechanisms of cardiac glycosides are specified.

Cardioactive steroid poisoning from an herbal cleansing preparation

We describe a case of unintentional poisoning from a cardioactive steroid and the subsequent analytic investigation. A 36-year-old woman with no past medical history and taking no conventional medications ingested an herbal preparation marketed for "internal cleansing." Its ingredients were neither known to the patient nor listed on the accompanying literature. The next morning, nausea, vomiting, and weakness developed. In the emergency department, her blood pressure was 110/60 mm Hg, and her pulse rate was 30 beats/min. Her ECG revealed a junctional rhythm at a rate of 30 beats/min and a digitalis effect on the ST segments. After empiric therapy with 10 vials of digoxin-specific Fab (Digibind), her symptoms resolved, and she reverted to a sinus rhythm at a rate of 68 beats/min. Her serum digoxin concentration measured by means of the fluorescence polarization immunoassay (Abbott TDx) was 1.7 ng/mL. Further serum analysis with the Tina Quant digoxin assay, a more digoxin-specific immunoassay, found a concentration of 0.34 ng/mL, and an enzyme immunoassay for digitoxin revealed a concentration of 20 ng/mL (therapeutic range 10 to 30 ng/mL). Serum analysis by means of high-performance liquid chromatography revealed the presence of active digitoxin metabolites; the parent compound was not present. When the diagnosis of cardioactive steroid poisoning is suspected clinically, laboratory analysis can confirm the presence of cardioactive steroids by using immunoassays of varying specificity. An empiric dose of 10 vials of digoxin-specific Fab might be beneficial in patients poisoned with an unknown cardioactive steroid.

Cardiovascular glycoside-like intoxication following ingestion of Thevetia nereifolia/peruviana seeds: a case report

Some plants contain glycoside compounds which determine cardiovascular symptoms similar to those observed after acute toxic digoxin administration. The present case report involves a patient who showed important cardiovascular symptoms following the ingestion of Thevetia nereifolia/peruviana seeds. About 30 min after ingestion, a 65-year-old man presented with dizziness, giddiness, numbness and a burning sensation, diarrhea, sweating, vomiting and ECG changes. At the time of admission he presented with tremors; his body temperature was 37 degrees C, and blood analysis gave the following results: K 5.6 mEq/l, myoglobin 176 IU, troponin T 0.10 ng/ml, PO2 69 mmHg, PCO2 37.4 mmHg, pH 7.33, HCO3- 19.9 mEq/l, hemoglobin 14.8 g/dl, saturation 92.5%. Echocardiography showed a left ventricle with normal global and segmentary contractility. The following days, the patient showed a reduction, until total resolution, of the atrioventricular block and of the alterations of the ST segment. The ectopic beats also resolved; K value before discharge was 4.4 mEq/l. On the third day, the serum levels of digoxin were 0.15 ng/ml. This case report is important because it describes all the cardiovascular and non-cardiovascular signs of glycoside toxicity in an adult patient who accidentally swallowed only two seeds (non-fatal dose) of Thevetia.

[Cardiovascular disturbances in acute poisoning--mechanisms and management]

The authors present the most common in clinical toxicology cardiovascular disturbances and mechanism of action the selected drugs (tricyclic antidepressants, cardiac glycosides, beta-blocking agents and calcium channel blockers). General management in acute poisoning with these drugs is also presented, concerning their toxicodynamics.

Anti-digoxin Fab fragments in cardiotoxicity induced by ingestion of yellow oleander: a randomised controlled trial

BACKGROUND

Severe cardiac glycoside cardiotoxicity after ingestion of yellow oleander seeds is an important problem in rural areas of Sri Lanka. Currently, patients must be transferred to the capital for temporary cardiac pacing. We did a randomised controlled trial to investigate whether anti-digoxin Fab could reverse serious oleander-induced arrhythmias.

METHODS

After a preliminary dose-finding study, 66 patients who presented to hospital with a serious cardiac arrhythmia were randomised to receive either 1200 mg of anti-digoxin Fab or a saline placebo. A 12-lead electrocardiogram, 3 min rhythm strip, and blood sample for measurement of electrolytes and cardiac glycosides were taken before treatment and at 12 timepoints thereafter.

FINDINGS

34 patients received anti-digoxin Fab and 32 received placebo. The presenting arrhythmia had resolved completely after 2 h in 15 antibody-treated patients and two controls (p<0.001); 24 and five patients, respectively, were in sinus rhythm at 8 h (p<0.001). Kaplan-Meier analysis of time to first reversal showed a significant response to anti-digoxin Fab. The heart rate increased in cases, from 49.1 per min at baseline to 66.8 at 2 h, but not in controls (50.6 per min at baseline to 51.5; p<0.001). Mean serum potassium concentrations decreased from 4.9 mmol/L to 4.1 mmol/L at 2 h in cases; no such decrease occurred in controls.

INTERPRETATION

Anti-digoxin Fab fragments are a safe and effective treatment for serious cardiac arrhythmias induced by yellow oleander. Their use in small rural hospitals in Sri Lanka should minimise costly transfer of patients and reduce the numbers of deaths; however, further study will be required to confirm this reduction.

A krimpsiekte-like syndrome in small stock poisoned by Ornithogalum toxicarium Archer & Archer

Krimpsiekte (the syndrome associated with chronic cardiac glycoside poisoning) was purportedly induced by Ornithlogalum toxicarium in the Karas mountains area of Keetmanshoop, Namibia. This chinkerinchee species was previously linked to a condition known as 'kwylbek' krimpsiekte in small stock in the Beaufort West district of the Western Cape Province, South Africa. In a dosing trial, respiratory distress, tachycardia and sternal recumbency were observed in 2 sheep drenched with fresh plant material. A fluorescence polarisation immunoassay (FPIA) detected the presence of a substance that cross-reacted with digoxin antibodies in some of the plant material collected at Keetmanshoop and Beaufort West. This is the first time that apparent cardiac glycoside poisoning was induced by a southern African chinkerinchee species. The presence of the cardiac glycoside-like substance in O. toxicarium requires further chemical verification.

Epidemic of self-poisoning with seeds of the yellow oleander tree (Thevetia peruviana) in northern Sri Lanka

Deliberate self-harm is an important problem in the developing world. Ingestion of yellow oleander seeds (Thevetia peruviana) has recently become a popular method of self-harm in northern Sri Lanka -- there are now thousands of cases each year. These seeds contain cardiac glycosides that cause vomiting, dizziness, and cardiac dysrhythmias such as conduction block affecting the sinus and AV nodes. This paper reports a study of the condition's mortality and morbidity conducted in 1995 in Anuradhapura General Hospital, a secondary referral centre serving 750 000 people in Sri Lanka's north central province. 415 cases were admitted to the hospital during 11 months; 61% were women and 46% were less than 21 years old. A prospective study of 79 patients showed that 6% died soon after admission. 43% presented with marked cardiac dysrhythmias which necessitated ther transfer to the coronary care unit in Colombo for prophylactic temporary cardiac pacing. The reasons for the acts of self-harm were often relatively trivial, particularly in children; most denied that they wished to die. Unfortunately, the case fatality rate for oleander poisoning in Sri Lanka is at least 10%. This epidemic is not only causing many unnecessary deaths, it is also putting immense stress on the already stretched Sri Lankan health services. There is an urgent need for an intervention which could be used in rural hospitals, thus preventing the hazardous and expensive emergency transfer of patients to the capital.

Krimpsiekte in a sheep following a single dose of Tylecodon ventricosus (Burm. f.) Toelken and the isolation of tyledoside D from this plant species

Tylecodon ventricosus induced severe respiratory distress in two penned sheep without any electrocardiographic abnormalities being recorded. Based on the results it appears as if T. ventricosus predominantly induces the neuromuscular syndrome referred to as krimpsiekte. A single, relatively large intraruminal dose of 10.0 g/kg induced krimpsiekte in one sheep. Treatment with 5.0 g/kg activated charcoal on two consecutive days did not prevent the development of krimpsiekte. A bufadienolide, tyledoside D, was isolated from semi-dried plant material.

Suspected cardiac glycoside intoxication in sheep and goats in Namibia due to Ornithogalum nanodes (Leighton)

The main clinical and necropsy features of field and experimental cases of suspected cardiac glycoside intoxication following ingestion and dosing of the plant Ornithogalum nanodes, are described. The distribution of intoxication in the area as well as a description of the plant are given. Plant samples tested for cardiac glycosides by fluorescence polarization immuno-assay (FPIA) gave a strong positive reaction. This is a new finding, as other toxic Ornithogalum species in southern Africa are devoid of cardiac glycoside activity and poisoning with them result only in a severe, often fatal diarrhoea, without obvious cardiac involvement. It is also the first record of toxicity of this particular plant.

Krimpsiekte, associated with thalamic lesions, induced by the neurotoxic cardiac glycoside, cotyledoside, isolated from Tylecodon wallichii (Harv.) Toelken subsp. wallichii

The specific neurotoxic principle of Tylecodon wallichii (Harv.) Toelken subsp. wallichii, the cause of krimpsiekte in small stock, was isolated and identified as the previously described cumulative bufadienolide, cotyledoside. Krimpsiekte was experimentally induced in two sheep by the repeated intravenous administration of cotyledoside at the rate of 0.01-0.015 mg/kg body mass. On day 9, both animals developed clinical signs typical of krimpsiekte, which is characterized by tremors, paresis and recumbency. Both sheep had difficulty in controlling their hindquarters when attempting to lie down. No significant electrocardiograph abnormalities were detected during the experiment which confirms that cotyledoside at low doses does not overtly affect the electrical activity of the heart. No gross lesions were observed in the sheep. The most significant microscopic lesions comprised mild brain oedema and pronounced vacuolation of the white matter of thalamic nuclei. These lesions might explain some of the motor function deficiencies clinically observed in this syndrome. The previously held contention that these neurotoxic cardiac glycosides are indeed the cause of krimpsiekte is, therefore, confirmed.

Kalanchoe lanceolata poisoning in Brahman cattle in Zimbabwe: the first field outbreak

Field outbreaks of Kalanchoe lanceolata poisoning in cattle on a commercial farm in Zimbabwe are reported. The clinical signs and pathological lesions observed in field cases resembled those reproduced in an experimental cow and were consistent with acute cardiac glycoside poisoning.

Suspected cardiac glycoside poisoning in elephants (Loxodonta africana)

Two young (< 2 years old) elephants (Loxodonta africana) died suddenly and simultaneously at Ongava Game Reserve bordering on the Etosha National Park, Namibia. Both elephants showed lung congestion, epi- and endocardial haemorrhages and hyperaemic areas in the mucosa of the stomach and small intestine. Histopathology of the myocardium showed multifocal degeneration and necrosis of muscle fibres accompanied by haemorrhages. Parts of the leaves of the alien plant Cryptostegia grandiflora (Asclepiadaceae) were found in the intestinal tracts of the elephants. These findings suggested that the elephants died from heart failure after ingesting this plant which contains cardiac glycosides.

A quest for oleandrin in decayed human tissue

This forensic case taught us several lessons. First, there is a need for improved sample cleanup and treatment of severely decayed tissue samples when trace determinations of target analytes are needed. With the exception of a few reports the literature is lacking in information with regard to the most modern sample preparation techniques. Second, the coupling of LC/LC with tandem MS provides an effective means of "on-line" samples cleanup for complex sample matrices. The improvements in selectivity shown in Figure 3 reveal the analytical power available when these techniques are combined. Third, once we decided to use LC/LC/MS/MS, we were able to analyze more than 50 samples in a semi-automated fashion over approximately three days. The reliability and ruggedness of the combined techniques and equipment suggest this approach may have merit for common applications in which large numbers of biological samples (e.g., plasma and urine) must be analyzed. As a postscript, when this project was completed we proposed that the use of antibodies for isolating oleandrin and its relatives might be a more selective means for trace enrichment of the target analytes. For example, a high-pressure immunoaffinity column could have been coupled on line as column 1 in Figure 4. After pumping a relatively high volume of aqueous tissue extract through an immunoaffinity column during trapping and trace enrichment conditions, the column could be rinsed with phosphate-buffered saline. Then the pH could be lowered to unfold the antibody protein and allow release of the trapped analyte from this column with subsequent trapping on column 2 in Figure 4.(ABSTRACT TRUNCATED AT 250 WORDS)

[Acute heart failure and its treatment in cardiologic drug poisoning]

The causes of sudden cardiac arrest (SCA) and its associated early death were examined in 179 patients with acute intoxications due to amitriptyline, antiarrhythmic agents and cardiac glycosides. In the first hours of intoxication, various cardiac conduction disturbances were found to occur in 39.6% of the patients, among whom 11.7% died due to SCA predominantly in complete bundle-branch block. The cause of SCA was an acute (contractile) heart failure that had run as cardiogenic shock and been associated with the specific selective action of the agents in question on cardiomyocytes. Premodulation of acute heart failure with membrane protective agents (unithiol, alpha-tocopherol, hydrocortisone), pharmacological antagonists (novodrin, alupent, isoprenaline), and the cardiotonic agent dobutamine enabled acute heart failure to be effectively treated, hemosorption to be made in early periods and cardiac events to be abolished in 80% of the patients, SCA mortality rates decreased from 11.7 to 3.2%.

Cardiac glycoside poisoning involved in deaths from traditional medicines

Autopsy cases (from all areas of South Africa except the Cape Province) are referred for chemical investigation to the Johannesburg Forensic Chemistry Laboratory of the State Health Department. Over a 1-year period in 41 autopsies where death was presumed to have been caused by a herbal medicine, the presence of cardiac glycosides was sought and was found in 44%. Most of the cases were from the Transvaal, followed by Natal. Clinical histories of the patients revealed that gastrointestinal irritation was the most common syndrome experienced after traditional medicine administration (54%). It is concluded that in patients presenting with gastro-intestinal symptoms, presumably due to poisoning by traditional medicines, cardiac glycoside poisoning should be suspected.

[Poisoning with oleander leaves]

After ingestion of seven leaves of oleander (Nerium oleander) in a suicide attempt, a 37-year-old woman was admitted to hospital with symptoms of digitalis intoxication. The serum digoxin level on arrival was 5.69 nmol/l. The course was uneventful. The usefulness of digoxin radioimmunoassay to demonstrate poisoning with oleander (but not to predict the degree of toxicity) and the potential use of digoxin-specific Fab-antibody fragments in this situation are discussed.

[Determination of zimarin in urine]

Private technique of extraction isolation and purification, chromatographic detection and photometric determination of zimarin in urine is suggested. Detection limit is 0.01 mg, determination limit is 0.1 mg of glycoside in 100 ml of urine. Method makes it possible to detect 66-80% of zimarin added to 100 ml of urine in quantities 0.5-0.1 mg.

Detection of poisoning by plant-origin cardiac glycoside with the Abbott TDx analyzer

Cardiac glycoside poisoning caused by ingestion of plant material is common in tropical and sub-tropical areas. In evaluating the use of the Abbott TDx Digoxin II assay to detect such cases of poisoning, we found it a rapid and convenient method for confirming the ingestion of glycosides from the plants Nerium oleander, Thevetia peruviana, and Adonis microcarpa, and from the toad Bufo marinus. Here we report some clinical cases illustrating our experience with the use of this assay, and describe results of cross-reactivity studies with compounds structurally similar to digoxin. Because of the competitive nature of the immunoassay as well as the complexity of the mixture of cross-reacting cardiac glycosides present in the plant material, the measured apparent digoxin concentration is not linearly related to the cardiac glycoside concentration.

Oleander poisoning: treatment with digoxin-specific Fab antibody fragments

A 37-year-old man presented two hours after the ingestion of "a handful" of oleander leaves (probably Nerium oleander) in a suicide attempt. Cardiotoxicity was evidenced by the presence of bradycardia (rate, 30 to 45) with sinoatrial nodal arrest and junctional escape consistent with a cardiac glycoside effect. The patient was treated empirically with a single dose of five vials (200 mg) of digoxin-specific Fab antibody fragments (Digibind). The pretreatment digoxin level was 1.5 ng/mL. After treatment, the patient's rhythm stabilized with residual sinus bradycardia (rate, 56). The patient recovered uneventfully and was discharged on the fifth hospital day to inpatient psychiatric care.

Cardiac glycoside poisoning in sheep caused by Urginea physodes (Jacq.) Bak. and the isolated physodine A

Urginea physodes (Jacq.) Bak., a species closely related to or possibly synonymous with U. pusilla, is described and its distribution given. Four bufadienolides were isolated from U. physodes and the approximated LD50 and cumulative effect of some of them determined in guinea pigs. The most toxic one proved to be mildly cumulative. Typical signs of acute cardiac glycoside poisoning, involving the locomotory, gastro-intestinal, respiratory and cardiac system, were seen in the field cases and/or were experimentally induced by the plant. Similar signs could also be induced by injecting the isolated bufadienolide, physodine A, to a sheep.

The toxicity to cattle and bufadienolide content of six Bryophyllum species

Cardiac glycoside poisoning was produced in calves given (in descending order of toxicity) flower heads of the hybrid Bryophyllum (Kalanchoe) daigremontianum x B. tubiflorum, of B. pinnatum, of B. tubiflorum (from previous work), whole plant of B. fedtschenkoi, flower heads of B. daigremontianum and whole plant of B. proliferum. For each plant (except B. tubiflorum), 2 calves were each given a single dose of 20 g wet weight per kg bodyweight. By using high performance liquid chromatography, the bufadienolides (cardiac glycosides) bryotoxin A, B and C were detected and assayed in the flower heads and leaf plus stem of B. tubiflorum and in the roots of B. tubiflorum, the hybrid and B. pinnatum. Only bryotoxins B and C were detected and assayed in the flower heads and leaf plus stem of the hybrid, B. daigremontianum and B. pinnatum. No bryotoxins were detected in B. fedtschenkoi. Bryotoxin A and a mixture of bryotoxins B and C from B. tubiflorum flowers were used as standards in the chromatographic assay. Comparing the results of the calf toxicity experiment with the amounts of bufadienolide measured in the plants suggests that bryotoxins A, B and C probably account for the observed disease, but that B. pinnatum and B. fedtschenkoi contain at least one other cardiac glycoside.

Oleandrin distribution in a fatality from rectal and oral Nerium oleander extract administration

In a fatal (cardiotoxic) case of oleander extract poisoning of a young female, ethanol extracts of blood and tissue homogenates were purified by lead acetate. After removal of excess lead by ammonium sulfate, oleandrin was extracted into chloroform. Oleandrin in the extract concentrates was detected by thin-layer chromatography, with location by fluorescence and chromogenically by means of p-anisaldehyde. Quantitation was performed on dried extracts reconstituted in water/methanol, reacted with hydrogen peroxide, ascorbic acid, and hydrochloric acid, and analyzed by fluorescence spectrophotometry. Excitation was at 355 nm, and fluorescence scanning from 340 to 580 nm. The fluorescence peak at 460 nm was used for the quantitative measurement. The concentrations of oleandrin measured in blood, stomach wall, colon tissue, liver, heart, lung, brain, spleen, and kidney ranged from 10 to 39 micrograms/g, with 200 micrograms/mL in the total gastric content residue submitted for analysis.

Curing experimental Bryophyllum tubiflorum poisoning of cattle with activated carbon, electrolyte replacement solution and antiarrhythmic drugs

A slurry of activated carbon (activated charcoal) in electrolyte replacement solution given by stomach tube and antiarrhythmic drugs given parenterally cured 9 of 11 calves dosed 7 to 24 h previously with a lethal amount (20g/kg) of Bryophyllum tubiflorum flower heads. Two of another 4 calves treated 26 to 36 h after dosing with flowers survived. B. tubiflorum toxins are bufadienolides (cardiac glycosides). Activated carbon was effective at a single dose of 5 g/kg. Calves were rehydrated with oral electrolyte replacement solution at 150 ml/kg in divided doses over 24 h. Tachycardia was treated with intravenous lignocaine (200 mg doses) or propranolol (5 mg doses) and atrioventricular block with atropine (0.5 mg/kg).

Herbal poisoning: a case report of a fatal yellow oleander poisoning from the Solomon Islands

A fatal yellow oleander herbal poisoning is reported in a 2 1/2-year-old Melanesian boy, who had persistent vomiting,bradycardia caused by complete heart block, hyperkalemia and cardiac glycosides detected in his serum. This is one of the few recognized clinical pictures of illness from herbal poisoning, yet herbal poisoning in infants in some Pacific and African countries is common and has a high mortality.

Poisoning by antidysrhythmic drugs

This article discusses the management of antidysrhythmic drug overdoses in children and adolescents.

Naturally occurring cardiac glycosides

Cardiac glycoside poisoning from the ingestion of plants, particularly of oleanders, occurs with reasonable frequency in tropical and subtropical areas. We have assessed a variety of plant specimens for their cardiac glycoside content by means of radioimmunoassays with antibodies that differ in their specificity for cardiac glycosides. Significant amounts of immunoreactive cardiac glycoside were found to be present in the ornamental shrubs: yellow oleander (Thevetia peruviana); oleander (Nerium oleander); wintersweet (Carissa spectabilis); bushman's poison (Carissa acokanthera); sea-mango (Cerbera manghas); and frangipani (Plumeria rubra); and in the milkweeds: redheaded cotton-bush (Asclepias curassavica); balloon cotton (Asclepias fruiticosa); king's crown (Calotropis procera); and rubber vine (Cryptostegia grandifolia). The venom gland of the cane toad (Bufo marinus) also contained large quantities of cardiac glycosides. The competitive immunoassay method permits the rapid screening of specimens that are suspected to contain cardiac glycosides. Awareness of the existence of these plant and animal toxins and their dangers allows them to be avoided and poisoning prevented. The method is also useful for the confirmation of the presence of cardiac glycosides in serum in cases of poisoning.

[The antitoxic action of triamterene in cardiac glycoside poisoning]

The antagonistic effect of triamterene on the toxicity of cardiac glycosides was investigated in conscious rabbits using the infusion method. Pretreatment with triamterene (5 mg/kg and 10 mg/kg) significantly reduces the ouabain toxicity indicated by an increase of the dose producing arrhythmia (from 61 +/- 14 to 121 +/- 17 and 178 +/- 22 micrograms/kg, resp.) and lethality (from 114 +/- 18 to 236 +/- 5 and 329 +/- 11 micrograms/kg, resp.). The triamterene induced increase of plasma potassium concentration may contribute to the antitoxic effect, however, the effect persisted after the decrease of plasma potassium concentration (by addition of NaHCO3) to pretreatment values. Under the influence of digitoxin the antitoxic effect of triamterene (10 mg/kg) is also demonstrated by the delayed appearance of arrhythmias (113 +/- 3 min compared to 78 +/- 5 min) and of lethality (125 +/- 4 min compared to 92 +/- 6 min). Triamterene is not only a prophylactic but also a curative antitoxic agent in the digitalis intoxicated rabbit.

[Glycoside poisoning in experimental heart failure and its drug correction]

It has been demonstrated in experiments on 420 rats that antiadrenergic, antihistamine, antihypoxic, anabolic, antiarrhythmic and diuretic agents have different effects on the cardiotoxicity of strophanthine K for intact animals and in experimental heart insufficiency of different genesis. The pharmacological analysis revealed some risk factors capable of provoking glycoside intoxication in circulatory failure. Approaches to the goal-oriented drug correction of the risk factors are proposed.