Effect of oral administration of trazodone on physiological and echocardiographic variables in cats

Objectives The aim of the study was to evaluate the effects of trazodone on sedation, and physiological and echocardiographic variables in healthy cats.Methods This randomised, blinded, crossover study involved eight healthy adult cats receiving either a placebo or oral doses of trazodone (50 mg, 75 mg, 100 mg), with a washout period of at least 1 week between doses. Sedation, muscle relaxation and analgesia scores were assessed, along with physiological variables including systolic blood pressure (SBP), pulse rate (PR) and respiratory rate (RR) at baseline (T0) and at 30-min intervals after administration (T30-T240). Echocardiographic variables were measured at T0 and T90.Results In the trazodone groups, cats' sedation scores significantly increased compared with T0, with no significant changes in muscle relaxation or analgesia scores. A significant mean reduction of 22 +/- 7 mmHg in SBP was observed only at T150 after oral administration of 100 mg trazodone compared with the placebo, but the SBP still remained within the reference interval. Across all trazodone doses, PR showed no significant changes, while RR significantly decreased compared with T0. There were no significant changes in echocardiographic variables after administration of three different doses of trazodone.Conclusions and relevance Oral administration of 50 mg, 75 mg or 100 mg of trazodone in cats produces mild sedation but there is a lack of muscle relaxation and analgesic effects. Trazodone has minimal effects on SBP, PR and RR in cats, although the 100 mg dose may cause a slight decrease in SBP within the physiological interval. Furthermore, oral trazodone at the tested doses has no impact on echocardiographic variables.