Pilot Study on QTc Interval in Dogs Treated with Domperidone

Simple Summary In humans, a pro-arrhythmic side effect of domperidone is caused by prolonged QT intervals. We evaluated this risk in dogs by measuring the corrected QT (QTc) intervals in 17 dogs receiving a four-week treatment. Electrocardiogram and blood parameter concentrations of creatinine, urea nitrogen, sodium, potassium, and chloride were evaluated seven days before the start and on the last day of therapy. In two dogs, the QTc interval was measured at four different times on the first day of treatment: before, 2 h, 3 h, and 12 h after administration of the drug. The 17 dogs showed a significant increase in QTc and chloride concentrations, but QTc post-treatment slightly exceeded the upper reference limit only in one dog, and the electrolyte concentrations were always within the reference range. Conversely, creatinine concentrations decreased significantly after treatment. In the two dogs monitored during the first day of treatment, QTc measures were always within the reference range. Domperidone administration caused a slight prolongation of QTc interval, and we suggest that further studies should be made for a risk assessment of the drug in dogs with cardiac diseases, electrolytic imbalances, and those under treatment with drugs that increase QT interval or compete with domperidone metabolism.Abstract Domperidone is used as an immunomodulatory drug for Leishmania infantum infection and disease in dogs. However, a pro-arrhythmic side effect, caused by prolonged QT intervals, is reported in humans. This pilot study evaluated the corrected QT (QTc) interval in dogs treated with domperidone for preventive or therapeutic management of leishmaniosis. The electrocardiogram and blood concentration of creatinine, urea nitrogen, sodium, potassium, and chloride were evaluated seven days before the start and on the last day of therapy in 17 dogs receiving domperidone for four weeks. In two dogs, the QTc interval was measured before and 2 h, 3 h, and 12 h after administration of the drug on the first day of treatment. After treatment, QTc measures and chloride concentrations increased significantly, although the QTc value slightly exceeded the upper reference limit only in one dog, and chloride concentrations were always normal. Creatinine concentrations significantly decreased after therapy. In the two dogs monitored at different times on the first day of treatment, QTc values were always normal. Domperidone caused a slight prolongation of QTc interval, and further studies should be made for a risk assessment in dogs with cardiac diseases, electrolytic imbalance, and in those receiving drugs increasing QT interval or competing with domperidone metabolism.