Propranolol hydrochloride and activated charcoal as a treatment of experimental oleander poisoning in sheep.
Oleander is an evergreen shrub or small tree from 5 to 25-ft tall containing gummy sticky sap in the dogbane family Apocynaceae. The Apocyanaceae (dog banes) are sources of African arrow poisons (for example Carissa acokanthera, bushman's poison' and Strophanthus hispidus) and also contain many of the most beautiful but deadly tropical flowering shrubs such as Plumeria rubra, frangipani', Nerium oleander, common, pink or white oleander' and Thevetia peruviana, yellow oleander' . The main cardiac glycoside of N. oleander is oleandrin with a molecular formula of C32H48O9 and a molecular mass of 576.3 (Fig-1) [3,14].
Its flowers in the spring or summer are white, pink, yellow or red large clusters. All parts of the plant are toxic and Toxicity remains in dried leaves . The basis for physiological action of N. oleander cardenolides is similar to that of classic digitalis glycosides, i.e. inhibition of membrane Na+/K+ ATPase pump, resulting in deficit in conduction of electrical potential, leading to ventricular arrhythmias and eventually loss of myocardial contractility . The cardiac effects of the glycosides are due to direct cardiotoxicity and also to an indirect effect via the vagal nerve . In this study the effect of propranolol hydrochloride and activated charcoal were considered to treatment of cardiac disturbances of oleander (Nerium oleander) intoxication in sheep.
Material and method
Seven clinically healthy male native Iranian sheep, 8-12 month, weighting between 25-41.3 kg were used for the study. The animals were purchased from a farm in suburb of Tehran. Fourteen days before the experiments, sheep were carefully examined and dewormed with albendazole (Tolid Daro, Iran).
Leaves from a certain oleander (Nerium oleander) tree with pink flower were collected sufficiently and then cleaned and dried at room temperature. After drying, leaves were finely grounded to powder. The powder of oleander leaf was administrated orally to sheep in form of aqueous suspension as a single lethal dose of 110 mg/kg body weight using the stomach tube.
The clinical signs were examined carefully and electrocardiograms were recorded using a base-apex lead (BTL-England). ECG and clinical signs were recorded with 15-min intervals after oleander administration. In treatment group, one hours after administration of oleander leaves, activated charcoal (Merck co.) Administrated via stomach tube. Immediately after producing of ventricular arrhythmias, propranolol hydrochloride was slowly administrated intravenously with dose of 5mg/head and repeated every 15 minutes in cases of maintening of ventricular tachycardia up to disappearing of ventricular arrhythmias.
[FIGURE 1 OMITTED]
Result and discussion
Clinical and ECG findings:
Sheep in control group (n=2) developed clinical signs of oleander toxicosis within 60 minutes after dosing of the plant. Clinical signs such as abdominal pain, manifested by restlessness, teeth grinding or groaning also dyspnoea, depression, ruminal atony with moderate to severe tympany, bloat, diahrrea and dehydration were evident. Additional signs including drooling of saliva, tenesmus, dribbling of urine and muscular tremor (table 1).
Both sheep in control group showed ventricular dysrrhythmia in late stage and died few minutes after occurring ventricular fibrillation. These sheep died within 41 to 56 hours (median 48.5 hours) after receiving the toxic dose.
Sheep in treatment groups (n=5) showed clinical signs of oleander toxicosis within 50-60 minutes after dosing of the plant. Clinical signs such as restlessness, grinding of the teeth, anorexia, constipation, frequent urination and ruminal atony were the most common signs for intoxicated sheep. Body temperature remained within normal limits during the experiment. All sheep in treatment group were administrated by activated charcoal (5 gr/kg, single dose) One hour after dosing with oleander leaves, via stomach tube. In 3 sheep of treatment group there was no cardiac arrhythmia and so they had no treatment by propranolol hydrochloride. In two rests, cardiac dysrrhythmia were evident and treatment was done by propranolol hydrochloride (5 gr/head) IV injection.
One sheep of two was died after 81 hours even after 6 doses of propranolol hydrochloride with 15 minutes interval. Ventricular tachycardia has changed to sinus tachycardia and AV block during the treatment but it finally changed to ventricular tachycardia and ventricular fibrillation and death. The serial ECG changes in this case from dosing up to death are shown in figure 2.
[FIGURE 2 OMITTED]
[FIGURE 3 OMITTED]
Another sheep that took the propranolol hydrochloride regime was lived after showing ventricular tachycardia. This case took 16 doses of propranolol hydrochloride during 3 days after induction of toxicity and showed multiple dysrrhythmias. The serial ECG changes in this case are shown in figure 3.
Oleander contains two potent cardiac glycosides or cardenolides, oleandrin and neriine, which are present in all parts of plant [6,10].
Cardiac glycoside are the most important toxic compounds of the oleander. The more known cardiac glycosides of the plant are oleanderin, folinerin and digitoxigenin. The toxicity of oleander cardiac glycosides is related to their ability in inhibition plasmalemmal sodium, potassium adenosine triphosphatase ([Na.sup.+], [K.sup.+]- ATPase), leading to sodium accumulation in excitable cells such as nervous tissue and myocardium [9,10]. The cardiac effects of the glycosides are due to direct cardiotoxicity and also to an indirect effect via the vagal nerve . In this study the main clinical signs observed were related to cardiac and gastrointestinal systems. The malignant and lethal effects of oleander were cardiac arrhythmias especially ventricular arrhythmias which finally led to ventricular fibrillation and death possibly due to more absorption of oleander toxins.
In this study bradycardia was the first arrhythmia noted 30 min after administration of oleander to sheep with development of toxicosis and several forms of tachyarrhythmia were found. Ventricular tachycardia were evident in two sheep. In one sheep, ventricular tachycardia goes to ventricular fibrillation and lead to death.
Diuretic effects of oleander toxicity are linked to direct effects of glycosides on renal tubules because sodium reabsorption in kidneys is an ATPase-dependent transport process. Whereas positive inotropic effect of glycosides, especially in early stages of poisoning, results in elevation of renal blood flow and increased glomerular filtration and diuresis .
There is no specific treatment for the poisoning, but procedures that are intended to reduce absorption or improve elimination of the toxin present in digestive tract, such as oral administration of activated charcoal, can be efficient in the early stages . Drugs like atropine, lidocaine, propranolol, phenytoin, metoclopramide, and epinephrine are all examples of such compounds and are given in response to specific cardiovascular symptoms (10). Tachycardia can be treated by application of the adrenergic blocking drugs such as propranolol. In this study propranolol hydrochloride was administrated in two sheep that showed tachyarrhythmia. In one sheep after 6 doses the cardiac rhythm not returns to sinus rhythm although some temporary sinus rhythm and sinus tachycardia were recorded. In another sheep the propranolol hydrochloride was effective and after 16 doses the cardiac rhythm was returned to sinus rhythm. So it is concluded that propranolol hydrochloride can be use in cases of oleander poisoning and may be need to administrate numerous doses.
The authors wish to acknowledge the council Research of Islamic Azad University, Sciense and Research Branch for the financial assistance.
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(1) Saeed Ozmaie, (1) Mehdi Sakha, (2) Ahmad Asghari
(1) Department of Clinical Science, Science and Research Branch, Islamic Azad University, Tehran, Iran.
(2) Department of Surgery, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Ahmad Asghari, Department of Surgery, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Table 1: Clinical signs in control and treatment groups No. Of ruminal animal diarrhea atony colic distress polyuria taypnea 1[c] + + + + ++ + 2[c] + + + + + + 3 + + + ++ ++ + 4 + + + - + + 5 ++ - - - - - 6 - - - - - - 7 + + + - - - [c] Controlgroup
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|Title Annotation:||Original Article|
|Author:||Ozmaie, Saeed; Sakha, Mehdi; Asghari, Ahmad|
|Publication:||Advances in Environmental Biology|
|Date:||May 1, 2011|
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