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Benzodiazepine Toxicosis 117

PHYSICAL EXAM FINDINGS can affect elimination and prolong clinical Behavior/Exercise
• Frequent: central nervous system (CNS) signs. If monitoring at home for mild ataxia, it is
VetBooks.ir • Common: hypotension, bradycardia, and • Prolonged or unmanaged severe clinical signs Drug Interactions Diseases and Disorders
○ Increase in liver enzymes and/or bilirubin
depression, sedation, ataxia, and weakness
safest to confine to prevent injury.
in cats that develop hepatic necrosis
hypothermia
• Possible: paradoxical excitation (e.g.,
tachycardia, agitation, vocalization); more (especially hypotension) may lead to bio- Barbiturates, other benzodiazepines, opioids,
chemical sequelae.
antidepressants, and any other sedatives may
common in cats increase CNS and respiratory depression.
• Rare: respiratory depression, coma Advanced or Confirmatory Testing
• Reported in cats with oral diazepam use: • OTC illicit drug urine tests may be of benefit. Recommended Monitoring
hepatic necrosis (idiosyncratic, cause unknown) False-positives may occur with sertraline or Monitor heart rate, blood pressure, body
with some nonsteroidal antiinflammatory temperature while symptomatic
Etiology and Pathophysiology drugs (NSAIDs) (e.g., oxaprozin, ibuprofen);
• Benzodiazepines are commonly prescribed false-negatives could occur because these PROGNOSIS & OUTCOME
as sedatives, muscle relaxants, and anxiolytics. screens do not detect all benzodiazepines.
They are also frequently used for acute • Diagnostic laboratory can confirm exposure Generally a good prognosis; veterinary patients
management of tremors and seizures. but blood concentrations are not clinically have a higher tolerance to benzodiazepines than
• They are available in an injectable form as relevant. humans.
well as in various milligram strengths of
tablets and rectal gels. TREATMENT PEARLS & CONSIDERATIONS
• Benzodiazepines increase gamma-
aminobutyric acid (GABA) activity. Because Treatment Overview Comments
GABA is an inhibitory neurotransmitter, it Symptomatic and supportive care is usually all • Cats and young dogs are overrepresented in
promotes generalized muscle relaxation and that is needed. Flumazenil can be given if signs paradoxical CNS excitation reactions
CNS depression. are severe. • For pregnant and lactating animals: single
• Benzodiazepines are metabolized in the liver. acute exposures do not likely pose significant
The active metabolites are conjugated Acute General Treatment risks to the fetus.
through glucuronidation (cats have limited • Emesis can be attempted in asymptomatic
capabilities for this). Excretion is through pets within 15-30 minutes of tablet ingestion Prevention
the kidneys. (p. 1188). Keep medications out of reach of pets.
• Pets with mild sedation or ataxia can be
DIAGNOSIS monitored at home. Technician Tips
• Activated charcoal is rarely needed. Have the owner bring the bottle with them to
Diagnostic Overview • Intravenous fluids can be used for hypoten- verify the drug, milligram strength, and number
Evidence of exposure at home or in hospital sion. Forced diuresis is not required. of tablets ingested and to determine if at risk
setting or the presence of clinical signs such as • Monitor body temperature. Use active for foreign body from any missing portions of
sedation, ataxia, weakness, or in some cases, warming as needed. the pill vial.
paradoxical excitement (e.g., vocalization, • Flumazenil 0.01 mg/kg IV, repeat in 1 to 3
agitation, tachycardia) can suggest the diagnosis. hours if needed: is a direct antagonist and Client Education
Over-the-counter (OTC) urine tests can be may be used if severe CNS, cardiovascular, Do not administer benzodiazepines to pets
used for a quick confirmation but are not or respiratory depression develops. without discussing with veterinarian.
validated in animals. ○ Use with caution because there could be
potential risk for arrhythmias or seizures. SUGGESTED READING
Differential Diagnosis • Acepromazine 0.02 mg/kg IV: has been Volmer PA: Recreational drugs. In Peterson ME,
• Sedative effects: opioids, barbiturates, phe- successfully used to manage paradoxical et al, editors: Small animal toxicology, ed 3, St.
nothiazines, cannabis, alcohols (ethanol, excitation. Do not treat stimulatory signs Louis, 2013, Elsevier, pp 309-334.
methanol, ethylene glycol), antidepressants, with a benzodiazepine. AUTHOR: Ginger Watts Brown, DVM
other anxiolytics • Diphenhydramine 1 to 2 mg/kg IM: can EDITOR: Tina Wismer, DVM, MS, DABVT, DABT
• Stimulatory effects: methylxanthines, be used for extrapyramidal signs (muscle
amphetamines, selective serotonin reuptake spasms, leg jerking) or dyskinesia (paddling,
inhibitors (SSRIs) vocalization).
Initial Database Chronic Treatment
• No serum biochemical changes expected with Cats with acute liver disease should be managed
acute overdose. Chemistry panel may reveal with intravenous fluid, antioxidants, and other
underlying renal or hepatic impairment that supportive care as needed (p. 442).

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