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Antidepressant (SSRI/SNRI) Drug Toxicosis 71

For example, decontamination is recom- (veterinary), or 25- and 50-mg chewable be used to determine the class of rodenticide
mended if a 20-lb (9-kg) dog eats tablets (veterinary). and the specific treatment required.
VetBooks.ir • Animals can ingest subtoxic doses over several Prevention SUGGESTED READING Diseases and Disorders
approximately 5 g (1 tsp) of 0.005%
brodifacoum.
• Keep all baits out of the reach of pets.
Murphy MJ, et al: Anticoagulant rodenticides. In
days, developing cumulative toxicosis.
ed 3, St. Louis, 2013, Saunders Elsevier, pp
pets.
• Anticoagulants can cause fetal loss at doses Rodents may drag packages within reach of Peterson ME, et al, editors: Small animal toxicology,
that are not toxic to the dam. • Baits are attractive to pets. Remove the bait 435-445.
• Vitamin K 1 injection (even when given SQ) from the animal’s environment. AUTHOR: Sharon M. Gwaltney-Brant, DVM, PhD,
can cause anaphylaxis in some animals. DABVT, DABT
• Injectable vitamin K 1 has no advantage over Technician Tips EDITOR: Tina Wismer DVM, MS, DABVT, DABT
oral vitamin K 1 therapy (both have similar The color and form (e.g., bar, pellet, tracking
bioavailability). powder) do not differentiate brands or active
• Vitamin K 1 comes as injectable (2 or 10 mg/ ingredients. The packaging lists active ingredi-
mL), 5-mg tablets (human), 25-mg capsules ents and the EPA registration number that can

Antidepressant (SSRI/SNRI) Drug Toxicosis Client Education
Sheet

BASIC INFORMATION leads to serotonin syndrome, which is to control tremors, body temperature, and
characterized by autonomic disturbances cardiovascular signs.
Definition (hypertension, tachycardia), neuromuscular
Toxicosis secondary to ingestion of a selective dysfunction (tremor), and altered mental Acute General Treatment
serotonin reuptake inhibitor (SSRI) or a sero- state (agitation, disorientation). • Emesis (p. 1188) if asymptomatic
tonin and norepinephrine reuptake inhibitor • SNRIs inhibit the reuptake of serotonin and • Activated charcoal (p. 1087) if asymptomatic
(SNRI). Toxicosis is characterized by sedation, norepinephrine. Both serotonin syndrome (not indicated if all pills quickly removed
ataxia, disorientation, and with increasing and more severe cardiovascular signs may through emesis)
doses, agitation, vocalization, tremors, and occur. • Cyproheptadine is a nonselective serotonin
cardiovascular signs. SSRIs include citalopram, antagonist and can help reduce serotonergic
escitalopram, fluoxetine, fluvoxamine, parox- DIAGNOSIS signs. Dogs: 1.1 mg/kg PO or rectally, can
etine, sertraline, vilazodone, and vortioxetine. repeat once in 4-6 hours if still symptomatic.
SNRIs include desvenlafaxine, duloxetine, Diagnostic Overview Cats: 2-4 mg/CAT PO
levomilnacipran, milnacipran, sibutramine, Diagnosis is usually based on a history of • Intravenous (IV) fluids to help regulate
and venlafaxine. ingestion and clinical signs. Blood levels can body temperature and blood pressure.
be obtained for some of the medications, but Fluids also help protect kidneys from sec-
Synonym they are not clinically relevant or timely. ondary damage from myoglobinuria due to
Serotonin syndrome Venlafaxine can give a false-positive result for rhabdomyolysis.
phencyclidine (PCP) on over-the-counter urine • If hyperthermia occurs, fans, alcohol sprays,
Epidemiology drug screens. etc.
SPECIES, AGE, SEX • For agitation: acepromazine 0.05 mg/kg IV
All species are susceptible. Differential Diagnosis or IM, titrate to effect as needed; or chlor-
• Toxicologic: 5-hydroxytryptophan (5-HTP), promazine 0.5 mg/kg IV, IM or SQ, titrate
RISK FACTORS anticholinergics, antihistamines, ethylene up as needed
Household members prescribed these medications glycol, hops, lead, monoamine oxidase inhibi- • For tachycardia: propranolol 0.02-0.06 mg/
tors, metaldehyde, tricyclic antidepressants kg IV, titrate up as needed
Clinical Presentation • Non-toxicologic: heat stroke, malignant • For tremors: methocarbamol 50-100 mg/kg
HISTORY, CHIEF COMPLAINT hyperthermia, meningitis (e.g., rabies, dis- IV, titrate up as needed
• History of exposure, evidence of chewed temper, meningitis of unknown cause), • For seizures: diazepam 0.5-2 mg/kg IV or
bottles neoplasia phenobarbital 3-4 mg/kg IV
• Sedation and ataxia or • Consider intralipids (p. 1127) in cases with
• Agitation, vocalization, and tremors Initial Database severe signs
• Vomiting, hypersalivation, diarrhea • No direct effects on liver or kidneys are
expected, but tremors and hyperthermia can Drug Interactions
PHYSICAL EXAM FINDINGS lead to alterations in renal and coagulation Avoid other SSRI or SNRI medications (e.g.,
• As above values. tramadol, ondansetron) (p. 1281).
• Dilated pupils, nystagmus, blindness • Blood gases in symptomatic cases (metabolic
• Hyperthermia acidosis) Possible Complications
• Tachycardia, hypotension • Hyperthermia: see Heatstroke (p. 421).
TREATMENT • Rhabdomyolysis: see Acute Kidney Injury
Etiology and Pathophysiology (p. 23).
• SSRIs are antidepressants that inhibit Treatment Overview
reuptake of serotonin. Serotonin is a mono- Decontaminate asymptomatic animals with Recommended Monitoring
amine neurotransmitter involved with sen- emesis and activated charcoal if indicated. Closely monitor heart rate, body temperature,
sorimotor function. Excessive stimulation Provide supportive care to symptomatic patients blood pressure, and urine color.

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