Peer-reviewed veterinary case report
Treatment of acute isoniazid overdose in dogs.
- Journal:
- Veterinary and human toxicology
- Year:
- 1995
- Authors:
- Villar, D et al.
- Affiliation:
- College of Veterinary Medicine · United States
Plain-English summary
Between 1987 and 1993, the National Animal Poison Control Center received 28 reports of dogs and cats exposed to isoniazid, a medication that can be dangerous if ingested in large amounts. The most common case involved a dog eating a single 300 mg tablet, which can lead to serious symptoms like repeated seizures and a state of confusion or unresponsiveness. The recommended treatment includes giving vitamin B6 through an injection and using anticonvulsants like diazepam to help control seizures. This combination has been shown to be effective in preventing further seizures and improving the chances of recovery, even after multiple seizure episodes. Overall, the treatment worked well in protecting the dogs from severe outcomes.
Abstract
The National Animal Poison Control Center received 28 calls of isoniazid (INH) exposures in dogs and cats between 1987 and 1993. The ingestion of a single 300 mg INH tablet was the most common complaint. Isoniazid has a low therapeutic margin and produces life threatening signs in dogs ingesting single 300 mg human tablets. The LD50 of INH in dogs is estimated at 50 mg/kg bw, which is probably similar to that for humans. However, rodents are among the species most resistant to INH and thus are not good animal models for toxic dose extrapolation. The more consistent clinical signs reported were recurrent clonic-tonic seizures followed by a stuporous state with poor response to stimulus. Ideal treatment combines vitamin B6 given as a single i.v. bolus at an equivalent dose to the amount of INH ingested and anticonvulsants such as 1 mg diazepam/kg bw. This combination acts synergistically to improve GABAergic transmission in the CNS and has proved effective in protecting animals from further convulsions and death, even after several seizure episodes, as often encountered in clinical situations.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/8592842/