EFFECT OF ORALLY ADMINISTERED OFLOXACIN ON LEAD II ELECTROCARDIOGRAM OF DOGS

Omobowale T.*, Afolabi J.M. and Amiwero O.

ABSTRACT

Introduction: Fluoroquinolones have been employed widely as antibiotic drugs in both human and veterinary medicine owing to their broad spectrum of antibacterial activity and excellent bioavailability. Life threatening arrhythmia has however been associated with the use of some them. This study was designed to study the possible effects of orally administered ofloxacin, a second-generation fluoroquinolone drug on the Lead-II electrocardiogram of dogs. Materials and Methods: Twelve Nigerian local dogs aged between 12 and 24 months were used in this study. Ofloxacin was orally administered at the dosage of 20mg/kg body weight daily for a period of 14 days. Lead II electrocardiographic readings were taken and measurements of the heart rate, P-wave duration, P-R interval, R-wave amplitude, QRS complex duration and QTC values were done. All clinical parameters were taken prior to administration of the drug and subsequently on days 3, 7 and 14 of treatment. Results: The major findings were a progressive increase in the heart rate from the day of the first dose to the 14th day and a significant increase in the QTc values through days 3, 7 and 14. Other parameters were however within normal range for dogs. Conclusion: This study showed that ofloxacin has a strong potential to cause QT prolongation in the dog, which could trigger the life threatening polymorphic ventricular tachycardia called Torsades de pointes in dogs. Therefore, its use in dogs should be with great caution.

Keywords: Ofloxacin, tachycardia, QT/QTc prolongation.