Hot Issue – Poisoning of Pets – Organophosphate and Carbamate Toxicity

Organophosphate and Carbamate poisoning of pets is common throughout the world. Deliberate poisoning of pets with these deadly compounds is more common in third world countries, where thieves poison pets with these illegal poisons in order to silence them before breaking into a house a few days later. In first world countries, where, these highly toxic poisons are better regulated, accidental poisoning of pets is more common, as access to the undiluted poison itself is very limited, but the poison is used as an ingredient in household pest sprays, in some tick and flea collars and tick and flea shampoos, and commercially in the agricultural industry.

[ad name=”Tweet”]


These poisons have two actions, known as the Nictonic effect and the Muscarinic effect. The Nicotinic effect causes muscle spasms, and can paralyze pets after poisoning.  The Muscarinic effect is far more deadly: It affects the internal organs – causing vomiting, diarrhoea, slows the heart down, and fills the chest up with fluid and eventually leads to death.

These poisons work by binding to the receptors on nerve endings and blocking them. This stops the nerves from working properly, animals collapse, vomit, have diarrhoea, struggle to walk and breathe, their hearts slow down so they can’t support life and then they die. These are terrible poisons and if you have them in your home, I would keep them locked up away from small children and pets.


These are much more commonly seen in dogs as cats may not show the classic symptoms, only depression or sudden death.

Muscle tremors and twitches – almost looks as if muscle is alive and worming around under the skin

Vomiting – if your pets has been maliciously poisoned you may see small black granules in the vomit


poison in dog vomit

Note the characteristic black granules in in the vomit with malicious poisoning

Diarrhea – Usually light coloured, just runs our of anus, anal area wet with loose stools



Doogs poisoned with pesticides are too weak to get up

This dog was unable to walk for 5 days after being poisoned

Difficulty breathing and heavy breathing

Constricted Pupils

Gums and Tongue are blue and there may be foam in the mouth


Blue colour tongue and gums due to pesticide poisoning

Cyanosis (blue color from too little oxygen) of the tongue due to fluid accumulating in lungs

Dog cannot stand up, legs seem uncoordinated and weak



dog having a seizure

A dog having a seizure or fit

Sudden death – depends on how much poison was taken in, but dogs can die within half an hour.


Temporary paralysis usually for 3-4 days but up to two weeks. These animals may need tube feeding as well as physiotherapy three to four times daily on an exercise ball to regain muscles strength.

Permanent paralysis due to muscles spasms causing a disc to slip in the neck

Twisted gut from the spasms in the intestine from the poisoning


Intravenous fluids (a drip) to support the heart and circulation

Intravenous fluids like Ringers lactate

Intravenous fluids for poisoning help prevent shock

Atropine slowly intravenously and under the skin to effect and repeated whenever symptoms recur.

Antidote for pesticide poisoning 2 step poisoning organophosphate poisoning dogs cats pets animals

Atropine is the antidote for poisoning

Diphenhydramine (a common antihistamine) helps to control twitches

Valium intravenously if seizures occur

Activated Charcoal orally to bind the poison in the intestine. This should be give for a few days as the body tend to absorb and re excrete the poison in the bile.

Soft bedding

Dogs that are not badly poisoned should be out of hospital the next day but dogs that have taken a lot of poison in may need to stay a few days.

If your vet has access to Pralidoxime or 2 PAM, these may be useful in cases of long term or chronic Organophosphate toxicity.


Definitive diagnostic tests measure levels of an enzyme called Cholinesterase in the blood, either in red blood cells or serum. This enzyme is affected by the poison.  It depends on your country and laboratory how long this test will take, but in some countries it takes up to two weeks, so most veterinarians will treat on the symptoms presented as waiting for the test to come back means your pet may die in the interim.

Blood can be tested for cholinesterase levels

Blood can be tested for enzyme levels indicating Organophosphate poisoning

If your pet has unfortunately passed away, your laboratory can test for levels of  Organophosphate or Carbamate in the Stomach contents. Often though, these poisons may not be easily picked up, especially if the post mortem is not done quickly as the poison tends to dissipate but most pathologists can look at the general condition of the body and give a probable cause of death.


Organophosphate poisons bind irreversibly to the nerve endings and sometimes a chronic form of this poisoning can be seen. Carbamate poisons are completely reversible with atropine. Chronic Organophosphate poisoning is usually seen with repeated exposure to the poison over time often with garden insecticides than the pet can easily gain access to and absorb through the skin, inhale or pick up by chewing on plants that have been sprayed. These pets can show weakness or paralysis of the extremities, persisting for weeks or years. Sometimes after an animal has taken in a big dose of poison, another syndrome of respiratory paralysis and weakness of the muscles can also be seen.


Have a look at the ingredients. if the long names contain the letters CARB or FOS, THION or PHOS, the odds are that it does. Another common name is Diazinon. Not all of these poisons follow these basic rules, so be sure to ask your veterinarian or poison center if you’re concerned.

[ad#Commission Junction Pet Insurance]

Leave a Reply