Pharmacokinetics and diuretic effect of bumetanide following intravenous and intramuscular administration to horses.

This research investigated the diuretic effect and time spent in a horse’s body system of the drug bumetanide after it was administered either intravenously or intramuscularly. The study showed that bumetanide is rapidly effective as a diuretic but disappears from the horse’s system relatively quickly, especially when administered intravenously.

Research Methodology

• The research team administered a dosage rate of 15 micrograms/kg of bumetanide to horses either intravenously or intramuscularly.
• They used a high performance liquid chromatographic procedure, which is a method used in biochemistry and analytical chemistry to identify, quantify and separate the individual components of a mixture, to determine concentrations of bumetanide in plasma and urine samples collected from the horses.

Findings

• The elimination half-life of bumetanide, which is the time required for the concentration of the drug in the body to be reduced by half, was found to be approximately 6.3 minutes.
• The study identified a volume of distribution at steady state (the theoretical volume that would be necessary to contain the administered dose at the same concentration that it is observed in blood plasma) of 68 ml/kg.
• The total plasma clearance (the volume of blood cleared of the drug per unit time) was noted as 10.9 ml/min/kg.
• The onset of diuresis, the increased production of urine by the kidneys, occurred within 15 minutes after intravenous administration of bumetanide, and stopped being apparent 1 hour after administration.
• When administered via the intramuscular route, the absorption of bumetanide was rapid and its bioavailability, which is the proportion of the drug that enters the circulation to exert its active effect, was between 70-80%. This intramuscular route also prolonged the plasma half-life of the bumetanide to between 11-27 minutes and intensifies and lengthens the diuretic effect of the drug.

This study impacts the veterinary medicine and horse racing industry as it offers information on how to best use the drug bumetanide to produce a diuretic effect in horses, as well as noting the drug’s short duration in the horse’s body system.