Phosphides Poisoning in Dogs

Zinc and aluminum phosphides are used for a variety of purposes. These phosphides are used in rodenticides, insecticides, and for protection of grain during its transportation and in stores. Zinc phosphide is contained in a variety of rodenticides, while aluminum phosphide is what is used as an insecticide to protect agriculture, animal feed, and commercial grains from pests. Both types of phosphides emanate an incredibly toxic phosphine gas which is dangerous for both animals and humans.

The inhalation of fumes that are released by phosphides or by accidental ingestion can cause poisoning. Phosphine is known to be an occupational hazard at .3 ppm and can be tolerated by people and some animals in the range of 1.5 - 3 ppm. Serious poisoning and possible death can occur at levels over 7 ppm.

Magnesium and aluminum phosphides are used as fumigants to control the rodents and insects within animal feed, on commercial farms, raw materials and agricultural ingredients for processed food, and to fumigate the tunnels and burrows caused by moles and other rodents. Both of these phosphides come in the form of pellets, tablets, and light dust. The similar compound, zinc phosphide, is primarily used as a killer of field mice, gophers, moles, and other pests. The bait that is developed using zinc phosphide is quite palatable and appetizing to the pests that it kills.

Phosphide poisoning in dogs occurs when toxic phosphide gas is inhaled or consumed by dogs. Phosphides are common ingredients in rodenticides and insecticides. The gas phosphides emit is life-threatening, and if poisoning occurs immediate medical attention is crucial.

Phosphide gas is highly toxic and flammable, and signs of phosphide poisoning occur within minutes. Symptoms can occur after ingestion of 1 tablespoon. Symptoms of phosphide poisoning in dogs include:

• Nausea
• Vomiting
• Shortness of breath
• Diarrhea
• Unwillingness to eat
• Convulsions
• Lethargy
• Confusion
• Paralysis
• Collapse
• Coma
• Death

Types

Phosphides are ingredients in a variety of products, namely rodenticides, but are also used to fumigate pests to protect agriculture and commercial food products. Types of products that contain phosphides are:

• Rumetan
• Phosvin
• Zinc-Tox
• Ratol
• Ridall
• Gopha-Rid
• Kilrat 
• Food storage facilities
• Rail transport of feed and grains
• Agricultural areas

The causes of phosphide poisoning in dogs is similar across all types of phosphides, such as magnesium, aluminum, and zinc phosphides. The causes of toxicity are:

• Ingestion of products containing phosphides
• Inhalation of products containing phosphides
• Phosphine gas is enhanced and rapidly released when combined with stomach acid

If you suspect your dog has come into contact with phosphides, you must get him to the veterinarian immediately. Fast-acting treatment can save your dog’s life. Before the veterinarian visit, or when you suspect poisoning, if your dog has vomited it is very important to remain above the vomit and to wash the area thoroughly with water. Phosphine gas is also highly toxic to humans, and if you come into contact with the dog’s secretions it is important not to get close to the substance, ventilate the area, and remain high above it, as phosphine gas weighs more than air.

The veterinarian may instruct as to how to make your dog vomit, and if this is the case, take him outside to do so. If your dog vomits in a poorly ventilated area, leave the area immediately and call 911. 

Once the dog is at the veterinarian’s office, the veterinarian will do initial testing of blood work, taking his temperature and checking his vital signs, venous blood gas analysis, serum chemistry profile, and any other tests he feels are necessary to make a diagnosis of phosphide poisoning. He will also want to know any information you have to give about the dog coming into contact with the product containing phosphides.

When treating a dog with phosphide poisoning, the veterinarian and staff will exercise extreme caution so they do not come into contact the poisonous gas. Treatment methods include:

Emesis

Inducing vomiting will help with the dog of the toxicity in the stomach and gastrointestinal tract. Inducing vomiting must be done very carefully, as the gas is highly toxic to humans. This must be done in a well ventilated area.

Gastric Lavage

Gastric lavage may be performed after emesis by the insertion of a tube into the stomach and to flush out the contents. During gastric lavage, the veterinarian will be very careful to protect the airway; in some cases a ventilator is used for respiratory distress.

Activated Charcoal

Activated charcoal will absorb any remaining poisons in the stomach before it is absorbed into the system of the dog.

Fluid Therapy

Fluids will be given to replenish the dog’s blood plasma, to help with any gastrointestinal acid or reflux, and to help the pulmonary system stay stable. Fluids may include famotidine, isotonic crystalloid, and N-acetylcysteine, all given intravenously.

Supportive Therapy

Controlling abnormalities of electrolytes, imbalances in acids and bases, and controlling hypoglycemia and seizures will require supportive care.

Antioxidants and Medications

Antioxidants help prevent damage to the body’s molecules and cells by reducing the toxic substance. Certain medications are given to promote detoxification and help replenish oxygen. They also help increase the concentration of hepatocytes, lung cells, and erythrocytes.

Recovery from phosphide poisoning in dogs depends on the severity of the dog’s condition and how he responded to treatment. Phosphide poisoning, even after treatment, can have long-term effects on many parts of the body’s organs, such as the kidneys, liver, brain, and heart. Every dog is unique, and every situation is different. Your veterinarian will explain to you the prognosis of your companion.

If you are able to take your dog home, it will be important to monitor your dog and follow your medical professional’s instructions for at-home care. He will tell you what to watch for in terms of symptoms that will require immediate medical attention, and if you have any questions about any new symptoms or behavioral changes, he will be there to answer your questions. Follow-up visits will be necessary to ensure your dog is recovering properly.