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Retrospective evaluation of toxicosis from selective serotonin reuptake inhibitor antidepressants: 313 dogs (2005–2010)


  • The authors declare no conflict of interests.

Address correspondence and reprint requests to

Dr. Danielle E. Thomas, Angell Animal Medical Center, 350 S Huntington Ave, Boston, MA 02130, USA.




To evaluate a clinical population of dogs exposed to selective serotonin reuptake inhibitor (SSRI) antidepressant medications and describe the clinical findings, epidemiological characteristics, outcome, and prognosis.


Retrospective study (February 1, 2005–August 31, 2010).


Animal poison control helpline.


Three hundred thirteen dogs with presumed SSRI toxicosis.



Measurements and Main Results

Dogs with presumptive SSRI medication toxicosis identified by a review of the electronic database of Pet Poison Helpline, an animal poison control center, were evaluated. No clinical signs were reported in 76.3% (239/313) of cases. The remaining 23.6% (74/313) of cases demonstrated the following clinical signs: neurological 79.7% (59/74), gastrointestinal 25.6% (19/74), cardiovascular 9.5% (7/74), respiratory 8.2% (6/74), and thermoregulatory 6.7% (5/74). Of the dogs exhibiting neurological signs, 62.7% (37/59) showed depression, 37.2% (22/59) showed hyperactivity, 10.1% (6/59) exhibited ataxia, and 1.7% (1/59) showed other miscellaneous signs (eg, hyperesthesia). There was a significant difference between the dose ingested by symptomatic and asymptomatic dogs for fluoxetine (P = 0.0039), but not with any other SSRI. Ninety-four patients were confirmed to have received veterinary care. In cases where duration of veterinary care was determined (55/313), 67.2% (37/55) of dogs were hospitalized and 32.7% (18/55) treated as outpatients. The average duration of hospitalization was 18.5 hours, excluding outpatient visits. Of those patients that had complete follow-up information available (136/313), overall survival was 100%.


The overall prognosis for animals with SSRI toxicosis is excellent with veterinary attention. Central nervous system depression was the most common clinical sign associated with SSRI toxicosis.