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

Abstract

Objective: 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.

Design: Retrospective study (February 1, 2005-August 31, 2010).

Setting: Animal poison control helpline.

Animals: Three hundred thirteen dogs with presumed SSRI toxicosis.

Interventions: None.

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%.

Conclusions: 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.