Читать книгу Canine and Feline Epilepsy - Luisa De Risio - Страница 127

Treatment includes administration of atropine (0.2 to 0.4 mg/kg, one-fourth of the initial dose slowly IV and the rest IM or SQ) to counteract the muscarinic signs, decontamination and prevention of further toxin adsorption (Table 4.1), skeletal muscle relaxants (Table 4.1), AEMs (see Table 4.1 and Chapters 12 and 24) and supportive care. Dramatic cessation of para-sympathetic signs is usually observed within 3 to 5 min after administration of atropine IV. Repeated administration of atropine, IV, IM or SC, at one-half of the initial dose is often required, especially in cats with organophosphate toxicity. Glycopyrrolate (0.01–0.02 mg/ kg IV) may also be used to control the muscarinic signs. Cardiac activity should be monitored. In animals with dermal exposure, decontamination is performed by bathing with a mild hand-dishwashing detergent and water. The individuals bathing the animals should wear protective gloves and aprons. In animals with oral exposure, decontamination is performed by induction of emesis (in asymptomatic animals) or gastric lavage and administration of activated charcoal with a saline cathartic or sorbitol (Table 4.1). Fluid therapy should be performed to correct possible dehydration, electrolyte imbalances and acidosis. Endotracheal intubation and ventilation may be necessary in cases of respiratory paralysis.

Pralidoxime chloride (2-PAM) is an AChE-reactivating oxime that acts specifically on the organophosphate-enzyme complex and counteracts the nicotinic cholinergic signs (Clemmons, 1990). Administration of 2-PAM should begin within 24 to 48 h of organophosphate intoxication as after this time the toxic compounds are irreversibly bound to AChE. The recommended dose is 10–20 mg/kg slowly IV with fluids over 30 min; or IM or SC. If nicotinic signs persist, the same dose can be repeated every 8–12 h, for 24 to 48 h. 2-PAM should be discontinued after three or four treatments if there is no response or nicotinic signs worsen. 2-PAM produces better results when atropine has already been administered; the atropine dose can be reduced when 2-PAM is used. Signs of muscle weakness and fasciculations usually disappear within 30 min. 2-PAM is not beneficial in treating carbamate toxicosis. If it is uncertain whether the toxicant is an organophosphate or a carbamate, 2-PAM should be used unless it is likely that the toxi-cant is carbaryl, in which case 2-PAM may be harmful. Administration of diphenhydramine (1 to 4 mg/kg PO every 8 h) has been recommended by one author to counteract the nicotinic signs 24 to 48 h after intoxication and to prevent signs of subacute intoxication (Clemmons et al., 1984; Clemmons, 1990). However, its use is controversial and other authors consider diphenhydramine contraindicated in animals with organophosphate and carbamate intoxication (Ellenhorn et al., 1997).