Abstract: Background – Trazodone, a serotonin antagonist and reuptake inhibitor (SARI) with alpha-adrenergic blocking effects, is an anxiolytic increasingly administered to dogs prior to veterinary visits. While trazodone appears to be well tolerated in dogs, its effects on echocardiographic and hemodynamic parameters are largely unknown.
Hypothesis/Objectives – To assess the effects of trazodone on blood pressure (BP), heart rate (HR), echocardiographic measurements, and sedation level in healthy dogs.
Animals - 31 adult dogs considered healthy based on physical exam (PE), M-mode and two-dimensional (2D) echocardiography, electrocardiogram (ECG), BP, blood chemistry, and urinalysis.
Methods – Prospective, double-blinded clinical trial. Dogs were randomized to receive standard (3-5 mg/kg) or high dose (10-12 mg/kg) trazodone at home 120-180 minutes prior to presentation. A washout period of at least 48 hours was mandated between doses. Sedation level, PE, BP, and echocardiography were performed at each visit.
Results - No clinically significant differences were found between baseline, standard, or high dose trazodone for HR, BP, or echocardiographic parameters including linear and volumetric left atrial and ventricular size and indices of systolic and diastolic function. There was a significant increase in sedation score between baseline (median 0, range 0-1) and standard dose (median 1, range 1-3) and between baseline and high dose (median 1, range 1-3) with no significant difference between standard and high dose.
Conclusion - A single dose of trazodone up to 12 mg/kg produces mild sedative effects in dogs within 120-180 minutes of administration and clinically insignificant changes to echocardiographic measurements, BP, and HR.
