Benzodiazepines
Benzodiazepines are used in human and veterinary medicine as sedatives, anxiolytics, and anticonvulsants
Kinetics:
Benzodiazepines are well absorbed from the GI tract and are widely distributed throughout the body.
They are highly protein bound and highly lipophilic.
Most are metabolized in the liver via glucuronide conjugation. Some benzodiazepines have pharmacologically active metabolites with half – lives exceeding those of the parent .
Mechanism of Action :
Benzodiazepines act on GABA receptors, triggering inhibitory impulses in the CNS and resulting in CNS depression.
Clinical Signs:
Clinical effects of benzodiazepines can occur as rapidly as 10 to 15 minutes following exposure. The clinical signs associated with benzodiazepine toxicosis include sedation, ataxia, and disorientation. Severely affected animals may become comatose, hypothermic, and hypotensive.
Seizures are possible, although uncommon, in comatose patients.
Diagnosis:
History , Clincal Signs
Blood and urine can be analyzed by most veterinary diagnostic laboratories for the presence of benzodiazepines.
Treatment:
- Minimize absorption of the drug and provide symptomatic and supportive care to animals experiencing CNS depression.
- Emesis may be induced followed by administration of activated charcoal and monitoring in hospital for 4 – 6 hours. Animals that present with severe CNS depression should not have vomiting induced due to the risk of aspiration; in these patients, gastric lavage should be considered.
- Activated charcoal administration should be repeated every 12 hours until the animals are ambulatory.
- Animals experiencing severe coma will need intensive supportive care. Endotracheal tube placement may be indicated in those animals with severe coma and subsequent respiratory depression; in some cases mechanical ventilation may be necessary.
- Oxygen and intravenous fl uids should be administered.
- Animals experiencing paradoxical excitation should be given a very low dose of acepromazine (0.01 to 0.02 mg/kg.