Antifreeze ingredients

Antifreeze products usually contain one of three active ingredients:

Ethylene glycol
Propylene glycol
Methanol
Ethylene glycol

Toxicity: Ethylene glycol is the ingredient found in most antifreeze products, usually at a concentration of 95-97%. It is an extremely dangerous toxin. The lethal dose for dogs is 2-3 ml/lb, and for cats it is 0.64 ml/lb. There are 15 ml in a tablespoon, so 2 tablespoons (30 ml) could be lethal for a 15-pound dog, and less than one-half of a tablespoon is lethal to a 10-pound cat. Smaller quantities can still make an animal critically ill. Antifreeze containing ethylene glycol has a sweet taste that animals and children like.

Ethylene glycol is metabolized by the liver. The metabolites that are produced cause damage to organs and the subsequent symptoms. The metabolites (in the form of oxalates) are most toxic to the kidneys. Ethylene glycol causes severe damage to the kidney, termed "acute renal tubular necrosis." Ethylene glycol also changes the pH of the blood to be more acidic (metabolic acidosis). Many brands of antifreeze also contain phosphorus rust inhibitors, which may increase the phosphorus levels in the bloodstream.

Signs of poisoning: There are three stages of ethylene glycol poisoning:

Stage 1: 0-12 hours after ingestion, nervous system signs develop including mild depression, ataxia, knuckling, seizures, hyperexcitability, stupor, rarely coma, and death. These signs are similar to acute alcohol intoxication and resemble drunkenness. Other symptoms may include lack of appetite, vomiting, drop in body temperature, and an increase in drinking and urination.
Stage 2: 12-24 hours after ingestion, cardiovascular system signs including increased heart rate and an increased respiratory rate can be seen.
Stage 3: 12-72 hours after ingestion, kidneys are affected. Symptoms include severe depression, vomiting, diarrhea, dehydration, kidney failure, and death.