Pharmacokinetics of erythromycin in foals and in adult horses.
Abstract: The pharmacokinetic parameters of erythromycin in foals were determined following intravenous administration of 5.0 mg/kg to animals aged 1, 3, 5 and 7 weeks. The distribution of the drug was described by a two-compartment open model, and no significant differences were observed between coefficients on which the parameters were based. Pharmacokinetic values were also determined for four mares given 5.0 mg/kg intravenously and for six 10-12-week-old foals given 20.0 mg/kg intravenously. The half-life of erythromycin for all groups of animals (foals less than 7 weeks, mares, foals 10-12 weeks) was 1.0-1.1 h; the apparent volume of distribution was between 2.3 and 7.2 l/kg, and the clearance of the drug from the body was between 1.9 and 5.0 mg/kg/h. No drug could be detected in the serum following oral administration of 5.0 mg/kg erythromycin estolate; detectable levels were found for 5 h in mares given 12.5 mg/kg, and for 8 h in foals given 20.0 mg/kg orally. Peak levels in foals given the drug orally were 0.42 micrograms/ml at 120 min after administration. Foals given 10.0 mg/kg of erythromycin base intramuscularly had serum concentrations detectable 12 h later; the peak level achieved was 1.44 micrograms/ml serum 90 min after administration and concentrations exceeded 0.25 micrograms/ml for 6 h. In the mares the milk concentrations were approximately twice those in serum. Recommendations were made for drug dosage to be used in the treatment of Corynebacterium equi pneumonia of foals.
Publication Date: 1983-03-01 PubMed ID: 6854734DOI: 10.1111/j.1365-2885.1983.tb00456.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article examines the metabolism and physiological distribution (pharmacokinetics) of erythromycin – a commonly used antibiotic – in foals and adult horses after intravenous injection. Factors reviewed include the half-life of the drug, its distribution volume, and its rate of removal from the body (clearance).
Methodology
- The scientists administered an intravenous dose of 5.0 mg/kg of erythromycin to foals at 1, 3, 5, and 7 weeks of age.
- The distribution of the drug was represented by a two-compartment open model. This model distinguishes the body into two compartments, i.e., the central compartment where the drug is initially distributed, and the peripheral compartment to which the drug gradually disperses.
- The same dosage was given to four adult mares, and a larger dose (20.0 mg/kg) was given to six foals aged 10 to 12 weeks for comparative study.
Results
- No significant differences were found between coefficients, suggesting a consistency in how the drug was metabolized at different ages.
- The half-life of erythromycin, which is the time taken for the concentration of the drug to decrease by half in the body, was between 1.0 and 1.1 hours in all groups tested.
- The apparent volume of distribution, which implies the degree to which the drug spreads within the body, was between 2.3 and 7.2 liters per kilogram.
- The drug clearance rate, describing the body’s efficiency in removing the drug, ranged between 1.9 and 5.0 mg/kg/hour.
- No erythromycin could be detected in the serum when orally taken at a dosage of 5.0 mg/kg. However, when a larger oral dose was given, it was found that the drug could be detected in the serum for up to 8 hours in foals and 5 hours in mares.
- When given intramuscularly, erythromycin persisted in the horse’s blood for up to 12 hours.
- In mares, the concentration of erythromycin in milk was approximately double that in the serum.
Implications and Recommendations
- The findings enable a determination of optimal dosages of erythromycin for treatment in horses, such as for Corynebacterium equi pneumonia in foals.
- Possible implications also include considerations for nursing mares, considering that the drug was found in higher quantities in milk.
Cite This Article
APA
Prescott JF, Hoover DJ, Dohoo IR.
(1983).
Pharmacokinetics of erythromycin in foals and in adult horses.
J Vet Pharmacol Ther, 6(1), 67-73.
https://doi.org/10.1111/j.1365-2885.1983.tb00456.x Publication
Researcher Affiliations
MeSH Terms
- Administration, Oral
- Animals
- Corynebacterium Infections / drug therapy
- Corynebacterium Infections / veterinary
- Erythromycin / administration & dosage
- Erythromycin / metabolism
- Female
- Half-Life
- Horse Diseases / drug therapy
- Horses / metabolism
- Injections, Intramuscular / veterinary
- Injections, Intravenous / veterinary
- Kinetics
- Male
Citations
This article has been cited 3 times.- Koenig J, Cote N. Equine gastrointestinal motility--ileus and pharmacological modification.. Can Vet J 2006 Jun;47(6):551-9.
- Takai S, Takeda K, Nakano Y, Karasawa T, Furugoori J, Sasaki Y, Tsubaki S, Higuchi T, Anzai T, Wada R, Kamada M. Emergence of rifampin-resistant Rhodococcus equi in an infected foal.. J Clin Microbiol 1997 Jul;35(7):1904-8.
- Riond JL, Müller P, Wanner M. The influence of age on the pharmacokinetics of aditoprim in pigs after intravenous and oral administration.. Vet Res Commun 1992;16(5):355-64.
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