1. Contact your veterinarian immediately.
  2. Your veterinarian may instruct you to induce vomiting, however, do not induce vomiting unless instructed to.
  3. Bring the medication your animal ingested along with the label or package insert to allow your veterinarian to calculate the dose received.
  4. If your pet has ingested more than one type of anti depressant, please notify your vet immediately as it increases the risk of your animal developing serotonin syndrome, which is life threatening and more complicated to treat.


Amitriptyline (Zeneka), amoxapine, clomipramine (clomicalm), desipramine (Nopramin), Doxepin, Imipramine (Tofranil), Nortriptyline, Protriptyline (Vivactil), Trimipramine (Surmontil).



The oral lethal dose for amitriptyline is 15mg/kg and that for clomipramine is 100mg/kg.


Clinical signs occur in 30 minutes to four hours following ingestion, depending on dose. At high doses, death may occur within 1-2 hours if left untreated.

  • Excitability/irritability/agitation
  • Lethargy
  • Uncoordinated gait (ataxia)
  • Tremors
  • Increased heart rate (tachycardia)
  • Irregular heart rhythm (arrhythmias)
  • Dilated pupils (mydriasis)
  • Dry mouth/sticky gums
  • Vomiting
  • Low blood pressure – faint, weakness, depression
  • Vocalisation
  • Difficulty breathing
  • Seizures
  • Coma
  • Death (usually due to cardiac arrest)


The exact mechanism of toxicity is unknown however, tricyclic antidepressants block the reuptake of neurotransmitters, norepinephrine and serotonin, causing increased levels of these neurotransmitters. They also affect intestinal motion and heart conduction.


Veterinary care consists of decontamination which may include gastric lavage and activated charcoal. Intravenous fluids, anti-convulsants and anti-histamines may be administered as required.


Plumb DC (2011) Plumb’s Veterinary Drug Handbook 7thEdn. Iowa, USA:Wiley-Blackwell

Wismer T (2000) Antidepressant drug overdoses in dogs. Veterinary Medicine. 95(7): 520-525

Wismer T (2006) Antidepressant Drug Overdoses. Veterinary technician. May: 278-281 aspcapro.org