Line of treatment :

1) Decontamination and detoxification– It is done to inhibit or minimize further toxicant absorption and to promote excretion or elimination of the toxicant from the body. Once the patient is stabilized, the assessment for decontamination can occur. It includes:

a. Ocular decontamination: -Flushing of eye with saline or tepid water to a natural pH for 15-20 minutes.

b. Dermal decontamination: -To prevent transdermal absorption of toxicant, but also to prevent oral reexposure secondary to grooming.

-Oil-based toxicities (e.g; high concentration pyrethrins) should be bathed off with tepid water and a liquid dish degreasing soap.

c. Inhalant decontamination: With exposure of an inhaled toxicant (e.g.: zinc phosphide rodenticides, carbon monoxide etc), treatment include administration of a humidified oxygen source, monitoring of oxygenation and ventilation.

d. Injection decontamination

Necessary when an animal has been exposed to an insect stinger or venom sac.

e. Gastrointestinal decontamination: It refers to functional removal of ingested toxin from gastrointestinal tract. It is done with gastric lavage or emesis, activated charcoal or whole bowel irrigation (utilizing a polyethylene glycol electrolyte balanced solution) for selected ingestions.

• Gastric lavage: Also called stomach wash or gastric suction, is the process of cleaning out of the contents of the stomach.

 Purpose – For urgent removal of ingested substance to decrease systemic absorption

               – To empty stomach before endoscopic procedure

               – To diagnose gastric hemorrhage and to arrest hemorrhage .

 It is indicated to empty the stomach immediately within 1 to 2 hours after an orally ingestion. Gastric lavage involves placing a tube through the mouth (orogastric) or through the nose (nasogastric) into the stomach. Toxicants are removed by flushing saline solutions into the stomach, followed by suction of gastric contents.

• Emesis: Emetic agent: apomorphine, xylazine.
• Whole bowel irrigation (WBI) -Done by enteral administration of large amounts of polyethylene glycol electrolyte solution until effluent (e.g: stool) is clear.
• Activated charcoal: It acts as an adsorbent and acts to prevent absorption of the toxicant. It is the primary treatment of choice for detoxification of the veterinary poisoned patient.

 Dose: 1-5 g per kg body weight, orally .

• Cathartics: Increase the speed and transit time of GIT, promoting faecal excretion of toxicant. Most common cathartics:

– Saccharide cathartics (e.g. sorbitol)                                                       

 – Saline cathartics (e.g. magnesium citrate, magnesium sulfate)

f. Surgical decontamination: Surgical removal of toxic agents is necessary if toxicant is caustic or corrosive .

2) Stabilizaition of emergent patient i.e ABCD:

a. Airway: Patient in coma, unconscious, neurologically impaired (absent gas reflex) or with dyspnea should be intubated with an endotracheal tube (ETT), connected to an oxygen source, and treated with positive pressure ventilative (PPV)

b. Breathing: Altered breathing may result in hypoxemia or hypoventilation. If the patient is not breathing, immediate intubation and PPV are indicated at 10-20 bpm, with a tidal volume of approximately 6-15 ml/kg

. c. Circulation: Altered circulation secondary to inadequate perfusion may be due to various toxicants: beta-blockers, calcium channel blockers etc. Appropriate therapy includes: fluid therapy, oxygen therapy if hypoxemia.

d. Dysfunction: Mental dysfunction may be due to various toxiacnts: excessive sedation (marijuana,opoid), agitation (SSRIs, caffeine), hypoglycemia (volatile alcohol, xylitol), neurological (ivermectin,amphetamines) others. If patient is hypoglycemic < 60mg/dl, administer 0.5-1.5 ml/kg of 50% dextrose IV, diluter 1:3 with a crystalloid, over 1-2 nimutes, followed by a CRI in IV fluids.

3) Supportive care and treatment:

As we know, very few toxicities have antidotes, treatment is often supportive. It includes:

a. Monitoring and supportive care: It includes:

• Continuous ECG: Poisoned patient may be at increased risk for the development of arrhythmias or severe electrolyte or acid-base abnormalities. Toxicant that require use of cECG monitoring care are: cardiac medications (beta-blockers, diagoxin, calcium channel blockers), SSRIs, amphetamine,amitraz etc.

• Blood pressure (BP): It should be monitored frequently in hypotensive patients, as it is a reflection of cardiac output, blood volume and vascular tone. It can be monitored by direct arterial blood pressure, Doppler or oscillometric measurement. In poisoned patient, hypotension may be seen from following toxicants: Cardiac medications (e.g. beta-blockers, calcium channel blocker), betaantagonist (albuterol, salmeterol, clenbuterol), sedative, anticoagulant rodenticide (e.g. bromediolone). 

• Urine output: It should be monitored and fluid therapy directed toward achieving normal urine output. Toxicant that require monitoring of urine output are nephrotoxicants (e.g. NSAIDs, ethylene glycol, grapes/raisins, etc. )

• Pulse oximetry : It is used in poisoned patient when dyspnea, tachypnea, abnormal lung sounds, or respiratory distress is evident.

• End-Tidal CO2: Use of End-Tidal CO2 to access the severity of hypercapnia (or hypoventilation)

• Blood gas analysis : Venous or arterial blood gas analysis is the deterimiantion of the pH, paO2 (arterial), PCO2 (venous or arterial), base excess (BE) and bicarbonate (HCO3) of blood.

b. Fluid therapy: Emergency management of poisoned patient to

 – Correct dehydration

 – Maintain perfusion at cellualar level

– Vasodilate the renal vessels, flush the renal tubules, diurese the patient.

 – Treats hypotension (toxicants such as beta-blockers, calcium channel blockers)

c. Cardiovascular support: In patient with cardiac arrhythmias, use of antiarrhythmic therapy is recommended

• Bradyarrhythmias (dog HR<50bpm; cat: HR<120 bpm)

-Atropine: 0.02-0.04 mg/kg IV, IM, SQ PRN bradycardia

-Glycopyrolate: 0.01 mg/kg IV, IM, SQ PRN bradycardia

• Supraventicular tachyarrhythmias (dog HR>180 bpm; cat : HR > 240 bpm)

– Esmolol: 250-500 μg /kg IV slow over two minute, then 10-200 μg /kg/min CRI.

 -Digoxin: Dog- 3-7 μg /kg PO q 12 hours.

• Ventricular arrhythmias – Lidocaine: Dogs: 2-4 mg /kg IV bolus,    

    Cat: 0.25 – 0.5 mg/kg IV bolus then 10-20 μg /kg/ min IV CRI.

d. Gastrointestinal support: Some toxin result in severe gastrointestinal ulceration (eg; aspirin ,veterinary NSAIDS: carprofen, firocoxib etc). Treatment should be initiated promptly and includes antiulcer. Treatment should be initiated promptly and includes antiulcer drugs:

•  H2 antagonist : cimetidine, famotidine, rantidine.
• Proton pump inhibitors: omeprazole, pantaprazole.
•  Sucralfate.
•  Antiemetic therapy: ondanseteron, metoclopramide

e. Analgesic/sedatives: Certain toxicities may result in severe agitation, where sedatives and analgesics should be used.

4) Antidotes: It is defined as substance used to relieve or prevent the effects associated with a toxicant. It modify the kinetics of toxic substance or interfere with its effect at receptor sites. Antidotes are broadly classified into 3 categories:

a. Chemical antidote: It works directly on toxicant. They bind with toxicant and form compound that is excreted from body.

•  Antivenom: In case of snake, black widow spider, or scorpion bite,IV antivenom can be used in dogs and cats to prevent paralysis, thrombocytopenia. Some antivenom are:

 – Elapid antivenin (coral snakes)             

   -Crotalid antivenin (pit vipers)

  -Black widow spider antivenin.

•     Chelating agents: It is used to treat heavy metal intoxication. It forms complexes with metals and prevent their binding to endogenous macromolecules. Some chelators are: -Calcium disodium ethylenediaminetetraacetic acid or CaNa2EDTA 

 -D-penicillamine  

-Deferoxamine 

 -Dimercaprol.

b. Functional antidotes: Functional antidotes have no chemical or physical interaction with toxicants but work to lessen the clinical signs associated with intoxication. Some functional antidotes are:

– Biphosphonates: specific antidote for vit.D3 toxicosis

 – Calcitonin: used to treat hypercalcemia

– Cyproheptadine: used to treat serotoninsyndrome

– Intravenous lipid emulsion: used to treat toxicosis associated with lipid- soluble drugs – Phytonadione: used to treat anticoagulant rodenticide toxicity

c. Pharmacological or physiological antidote: It works by several different mechanism. They work:- directly on receptor site

  – counteracting  toxicosis by producing opposing clinical signs

    – prevent formation of toxic metabolites   

 – facilitates more rapid elimination of a toxicant                      

  – aid in restoration of normal body function

• Atropine: It is muscarinic- receptor antagonist used an antidote for intoxication by the anticholinesterase. It acts by blocking access of excess acetycholine to muscarinic receptors used for treatment of SLUDGE

– Salivatiaon      

 – Urination      

  – Gastroenteritis     

  – Lacrimation     

  – Defecation  

 Dose: 0.2 – 2 mg/kg (dogs and cats)

•  Ethanol: Used as second line treatment for ethylene glycol toxicosis. Acts by inhibiting alcohol dehydrogenase.
• Fomepizole: indicated as specific antidote for EG toxicosis. It is competitive inhibitor of alcohol dehydrogenase.