Selective serotonin reuptake inhibitor (SSRI) toxicosis in cats: 33 cases (2004-2010)

To evaluate a population of cats with selective-serotonin reuptake inhibitor (SSRI) toxicosis and characterize the population affected, list products ingested, the clinical signs observed, treatments performed, length of hospitalization, patient outcome, and overall prognosis.

Retrospective study from 2004 to 2010.

Referral veterinary center.

Thirty-three witnessed cat SSRI ingestions.

None.

The medical records of cats with a witnessed SSRI ingestion identified by review of an animal poison control center electronic database were evaluated. The most common SSRIs ingested were venlafaxine (Effexor; 12/33; 36%), fluoxetine (Prozac; 12/33; 36%), citalopram (Celexa; 6/33; 18%), and escitalopram (Lexapro; 3/33; 9%). Overall, 24% of cats (8/33) became symptomatic, while 76% (25/33) remained asymptomatic. Of the symptomatic cats, sedation was the most common clinical sign (6/8; 75%), followed by gastrointestinal signs (4/8; 50%), central nervous system stimulation (1/8; 13%), cardiovascular signs (1/8; 13%), and hyperthermia (1/8; 13%). Veterinary care was sought in 20 cats (20/33; 61%). Sixteen cats (16/20; 80%) were hospitalized, while 4 cats (4/20; 20%) were treated as outpatients. Treatment for hospitalized patients included administration of IV fluid therapy (14/16; 88%), activated charcoal (12/16; 75%), anti-arrhythmic agents (7/16; 44%), methocarbamol (6/16; 38%), cyproheptadine (6/16; 38%), anti-emetics (5/16; 31%), and sedation (5/16; 31%). Diagnostics included blood work (7/16; 44%), blood pressure measurement (3/16; 19%), and electrocardiogram monitoring (2/16; 13%). Mean hospitalization time for all cases of SSRI ingestion was 14.6 ± 7.8 hours (n = 16). All symptomatic cats in this study (8/8; 100%) had resolution of clinical signs and survived to discharge.

The prognosis for SSRI ingestion in this population of cats was excellent. Decontamination and supportive care for at least 12-24 hours can be considered in cats with SSRI ingestion, particularly venlafaxine to monitor resolution of clinical signs.