TY - JOUR

T1 - Evaluation of electrocardiographic repolarization parameters after administration of trimethoprim-sulfadiazine, detomidine, or their combination in horses

AU - Trachsel, Dagmar S

AU - Calloe, Kirstine

AU - J Rgensen, Elin

AU - Lunddahl, Christine S

AU - Pedersen, Philip J

AU - Kanters, J Rgen K

AU - Klaerke, Dan A

AU - Buhl, Rikke

PY - 2021

Y1 - 2021

N2 - OBJECTIVE: To determine whether administration of trimethoprim-sulfadiazine (TMS), detomidine (DET), or TMS plus DET would be associated with changes in ECG repolarization parameters in horses.ANIMALS: 9 healthy adult horses.PROCEDURES: Each horse received 4 treatments in a blinded, randomized, crossover study design as follows: TMS, 16 to 24 mg/kg, IV; DET, 0.015 to 0.02 mg/kg, IV; TMS plus DET; and saline (0.9% NaCl) solution. Surface ECG traces were obtained over 24 hours, and repolarization parameters were measured at predefined time points after each treatment and compared with a 2-way ANOVA for repeated measures.RESULTS: Heart rate-corrected QT intervals (QTc) were significantly increased after administration of DET (mean ± SD difference in QTc, 36.57 ± 23.07 milliseconds; increase of 7%) and TMS plus DET (44.96 ± 29.16 milliseconds; increase of 9%), compared with baseline (before treatment) values and values after administration of saline solution. Saline solution and TMS alone did not affect QTc.CONCLUSIONS AND CLINICAL RELEVANCE: Administration of DET or TMS plus DET was associated with a significant and possibly clinically relevant prolongation of QTc, with prolongation of 7% to 9%, a range that is considered as a risk factor for the development of cardiac arrhythmias in people. Results were unexpected because DET is considered to be a safe sedative for horses.

AB - OBJECTIVE: To determine whether administration of trimethoprim-sulfadiazine (TMS), detomidine (DET), or TMS plus DET would be associated with changes in ECG repolarization parameters in horses.ANIMALS: 9 healthy adult horses.PROCEDURES: Each horse received 4 treatments in a blinded, randomized, crossover study design as follows: TMS, 16 to 24 mg/kg, IV; DET, 0.015 to 0.02 mg/kg, IV; TMS plus DET; and saline (0.9% NaCl) solution. Surface ECG traces were obtained over 24 hours, and repolarization parameters were measured at predefined time points after each treatment and compared with a 2-way ANOVA for repeated measures.RESULTS: Heart rate-corrected QT intervals (QTc) were significantly increased after administration of DET (mean ± SD difference in QTc, 36.57 ± 23.07 milliseconds; increase of 7%) and TMS plus DET (44.96 ± 29.16 milliseconds; increase of 9%), compared with baseline (before treatment) values and values after administration of saline solution. Saline solution and TMS alone did not affect QTc.CONCLUSIONS AND CLINICAL RELEVANCE: Administration of DET or TMS plus DET was associated with a significant and possibly clinically relevant prolongation of QTc, with prolongation of 7% to 9%, a range that is considered as a risk factor for the development of cardiac arrhythmias in people. Results were unexpected because DET is considered to be a safe sedative for horses.

KW - Animals

KW - Cross-Over Studies

KW - Electrocardiography/veterinary

KW - Heart Rate

KW - Horses

KW - Imidazoles

KW - Sulfadiazine

KW - Trimethoprim/adverse effects

U2 - 10.2460/ajvr.82.3.207

DO - 10.2460/ajvr.82.3.207

M3 - Journal article

C2 - 33629897

VL - 82

SP - 207

EP - 217

JO - American Journal of Veterinary Research

JF - American Journal of Veterinary Research

SN - 0002-9645

IS - 3

ER -