Toxciology Brief: Ibuprofen toxicosis in dogs, cats, and ferrets - Veterinary Medicine
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Toxciology Brief: Ibuprofen toxicosis in dogs, cats, and ferrets



Ibuprofen has a narrow margin of safety in dogs. One recommended dosage is 5 mg/kg/day, divided.3 However, signs of toxicosis have been seen with a dosage of 8 mg/kg/day for 30 days. At this dosage, no clinical signs were seen, but the dogs developed gastric ulcers and intestinal inflammation.6 At 16 mg/kg/day, vomiting, diarrhea, melena, and weight loss were evident by the eighth week of administration.6 In one case report, a dog given 3 mg/kg every other day for six weeks developed a fatal gastric perforation.7 Renal insufficiency or failure, impaired hepatic function, hypoalbuminemia, stress (such as recent surgery), or concurrent administration of glucocorticoids may increase the toxicity of ibuprofen administered long-term.7,8

An acute ibuprofen overdose in dogs, cats, ferrets, and humans is associated with gastrointestinal, renal, and central nervous system signs. Gastrointestinal signs are thought to be due to the inhibition of COX-1 enzymes and the loss of normal gastric protective mechanisms, though this may be an oversimplified explanation of the mechanism.9 Vomiting, abdominal pain, hematemesis, and diarrhea can be seen within 24 hours of ingestion.10 Single, acute overdoses as low as 25 mg/kg can cause vomiting in dogs (ASPCA APCC Database: Unpublished data, 2003).

At doses greater than 175 mg/kg, the risk of acute renal failure in dogs increases. In the kidney, prostaglandins are responsible for vasodilation and maintenance of the renal medulla's blood flow, especially during hypovolemic states. Ibuprofen blocks these vasodilatory prostaglandins. The resultant diminished renal blood flow can lead to acute interstitial nephritis, papillary necrosis, renal-tubular necrosis, and acute renal failure. Preexisting renal disease, hypovolemia (possibly from vomiting and concurrent dehydration), and hypotension can increase the risk of renal toxicity from ibuprofen.3

At doses greater than 400 mg/kg, central nervous system effects can be seen in dogs, including depression, seizures, and coma.11 The mechanism for these signs is unknown. The minimum lethal dose in dogs is about 600 mg/kg.11 In addition, hepatotoxicity (especially with long-term use) and inhibition of platelet function have been reported in humans.5

Table 1 Ibuprofen Dose and Associated Signs or Outcomes in Dogs*
Table 1 shows signs associated with increasing doses of ibuprofen in dogs. Cats, because of limited glucuronyl-conjugating ability, are thought to be twice as sensitive as dogs to ibuprofen's toxic effects.10

Ferrets are especially sensitive to ibuprofen's toxic effects. Because of their small size (an adult weight of 0.5 to 2 kg),12 ingestion of a single 200-mg tablet can result in a dose of 100 to 400 mg/kg. In one review of cases received by the ASPCA APCC, 93% of ferrets ingesting ibuprofen developed neurologic signs, including depression, coma, and ataxia. Slightly more than half the ferrets developed vomiting or diarrhea. The minimum lethal dose in ferrets was about 220 mg/kg.13


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