Adverse effects of trazodone in dogs on primary hemostasis and electrocardiogram: A single-blinded placebo-controlled crossover study.

BACKGROUND: Trazodone is a serotonin antagonist/reuptake inhibitor medication commonly used for anxiety in dogs. Therapy with selective serotonin reuptake inhibitors in humans is associated with bleeding disorders and increased arrhythmogenesis. HYPOTHESIS/OBJECTIVES: To evaluate markers of primary hemostasis and corrected QT (cQT) interval in dogs before and after oral administration of standard dosages of trazodone or placebo. ANIMALS: Fifteen apparently healthy, client-owned dogs. METHODS: A single-blinded, randomized placebo-controlled crossover study was performed. Dogs were administered trazodone (5 to 7.5 mg/kg PO Q12h) or placebo. [Correction added after first online publication on 14 October 2023. In the abstract (methods) section (57.5 mg/kg PO Q12h) changed as (5 to 7.5 mg/kg PO Q12h).] Buccal mucosal bleeding time (BMBT), platelet count, platelet aggregation via Plateletworks, PFA-100 closure time and cQT interval were measured. A Shapiro-Wilk test was performed followed by either a paired t test or a Wilcoxon signed-rank test. RESULTS: No significant difference was detected in the BMBT, PFA-100 closure times, platelet counts, and cQT interval between trazodone or placebo. However, using Plateletworks, there was a significant decrease in platelet aggregation after administration of trazodone (95%; 81-97 vs 62%; 39-89, P = .002) and not placebo (95%; 81-97 vs 91%; 81-96, P = .21). CONCLUSIONS: It is unknown if this represents a clinically relevant change or if dogs with preexisting impairment in primary hemostasis or receiving higher dosages or longer durations of trazodone could have a more substantial change in hemostatic variables.

Ionized calcium-to-phosphorus ratio predicts neoplasia in azotemic dogs: a retrospective study of 105 cases.

OBJECTIVE: To evaluate dogs with total hypercalcemia, azotemia, and normal serum phosphorus concentrations to determine whether a calcium-to-phosphorus ratio (Ca:P) or ionized Ca:P (iCa:P) could be utilized to predict underlying neoplasia. ANIMALS: 105 dogs were included in the study. Thirty-seven percent (n = 39) had known neoplasia, and 63% (66) had no evidence of neoplasia. PROCEDURES: A retrospective medical records search was performed. An observational cutoff of 2.5 for Ca:P and 0.33 for iCa:P was used for determining sensitivity and specificity between the neoplasia and nonneoplasia groups. RESULTS: Total hypercalcemia was higher in dogs with neoplasia compared to nonneoplastic cases of hypercalcemia. Ca:P of 2.5 had an 80% sensitivity and 46% specificity for predicting neoplasia. iCa:P of 0.33 had a 92% sensitivity and 77% specificity for predicting neoplasia in azotemic dogs. CLINICAL RELEVANCE: The sensitivity and specificity of Ca:P was low, making it an unreliable tool to predict neoplasia in this specific study population. However, iCa:P may have some usefulness in determining presence of neoplasia in patients with high calcium, azotemia, and normal phosphorus.