Phenytoin sodium as a treatment for ventricular dysrhythmia in horses.

The research tested the effectiveness of phenytoin sodium in treating ventricular dysrhythmia (irregular heart rhythms) in horses, after conventional treatments did not work. The study suggested that phenytoin sodium is an effective and affordable alternative treatment.

Research Context

• The study was conducted on five adult horses with ventricular extra systoles (VES) and two with ventricular tachycardia (VT).
• These conditions refer to abnormal heart rhythms, often leading to weak or irregular heart function.
• These horses were not responding to conventional treatments like rest, anti-inflammatory drugs, lidocaine, or procainamide.

Research Procedure

• Phenytoin sodium was administered orally every twelve hours to the horses under study.
• The starting doses were between 20 and 22 mg/kg body weight.
• The maintenance dose ranged between 8 and 17 mg/kg body weight.
• The researchers monitored the therapeutic blood concentration of total and free phenytoin during the experiment.

Research Findings

• The treatment abolished both VES and VT in all horses under study.
• An initial dose of 20 mg/kg body weight every twelve hours, followed by a maintenance dose of 10 to 15 mg/kg body weight, was suggested based on the research results.
• Phenytoin plasma concentrations should be monitored during therapy, as high concentrations led to adverse effects such as excitement and recumbency.

Conclusion

• Based on the results of the limited study, phenytoin sodium seems to be a cost-effective and efficient alternative treatment for persistent VES or VT in cases where standard treatment has proved ineffective.