[The plasma level of kanamycin after intravenous and intramuscular injections in horses].

The research investigated the efficacy of the antibiotic kanamycin in horses, showing how quickly it enters the bloodstream and revealing its potential for therapeutic use with minimal side-effects.

Methodology and Analysis

• The study tested doses of kanamycin, a type of antibiotic, in four standardbred horses.
• These doses were administered both intravenously (directly into the bloodstream) and intramuscularly (injected into a muscle).
• Plasma concentrations, or the concentration of the antibiotic in the blood, were measured for a 12-hour period to monitor how quickly and effectively the drug was dispersed and absorbed in the body.

Findings

• After the administration of the antibiotic, plasma levels were found to surpass the minimum inhibitory concentration (the lowest concentration required to inhibit bacterial growth) within just 15 minutes. This quick absorption was consistent both with intravenous and intramuscular injections.
• Over an 8 hour period, these adequate plasma levels of kanamycin were maintained, showing a sustained potency of the antibiotic in the bloodstream.
• The mean half-life of kanamycin in the plasma was approximately 2.3 hours, indicating that the body metabolizes and eliminates about one-half of the drug from the blood every 2.3 hours.
• The bioavailability (the rate and extent to which the active ingredient in a drug is absorbed and becomes available at the site of action) of an intramuscular dose of kanamycin was about 76%, demonstrating that a significant portion of the drug is effectively absorbed into the system when administered this way.

Implications

• The study recommends a dosage regimen for horses of two daily injections of 5 mg/kg body weight to ensure the therapeutic effectiveness of plasma levels.
• The risk of drug accumulation as well as serious side effects such as damage to the kidneys (nephrotoxic) or ears (ototoxic) are deemed negligible with short-term treatment.
• Overall, the pharmacokinetic parameters of the study demonstrate a rapid onset of antibacterial effectiveness of kanamycin in the horse’s body.