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Rifampin in the horse: comparison of intravenous, intramuscular, and oral administrations.
Abstract: The plasma concentrations and pharmacokinetics of rifampin disposition were determined after a single IV, IM, or oral dose of 10 mg/kg of body weight and an oral dose of 25 mg/kg. The overall elimination rate constants per minute were similar for the 10 mg/kg dose (0.0021 +/- 0.0004, IV; 0.0017 +/- 0.0002, IM; and 0.0023 +/- 0.0006, orally). The apparent bioavailability was moderate to low for IM and oral administrations (59.8% +/- 3.2% and 39.5% +/- 5.0%, respectively). The rate of absorption was most rapid for oral administration with an absorption half-life of 249.7 +/- 71.6 minutes as compared with 403.5 +/- 89.7 minutes for IM administration. However, the IM route produced longer detectable plasma concentrations (50 hours in 2 of the 4 horses). Based on bacterial sensitivity information derived for human and canine isolates, the daily oral administration of 10 mg of rifampin/kg administered in the feed represents a reasonable dose for susceptible gram-positive bacterial pathogens. Higher doses (greater than or equal to 25 mg/kg) or IV administration would be required for most gram-negative bacteria. Adverse effects of sufficient severity to limit use of the drug, especially by the oral route of administration, were not encountered under the single-dose experimental conditions used.
Publication Date: 1985-02-01 PubMed ID: 3994110 The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Comparative Study
- Journal Article
Summary
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The research article discusses a study on the comparison of intravenous (IV), intramuscular (IM), and oral administration of rifampin, a common antibiotic, in horses. The study focuses on observing respective routes’ effectiveness according to absorption, availability, and presence in plasma concentrations.
Analysis of Rifampin Administration
- The study administered a single dose of rifampin through IV, IM, or oral method to the horses. The main objective was to investigate the drug’s efficiencies through different administration routes.
- Different methods used the same dosage of rifampin -10 mg per kilogram of the horse’s body weight – along with a supplemental dosage of 25 mg per kilogram orally. This comparison permitted a thorough analysis of the absorption of rifampin in the animal’s body via the different routes.
Comparison of Disposition and Absorption Rates
- The overall elimination rate, which signifies how quickly the body purges the drug, was found to be relatively consistent amongst the three administration methods.
- However, the apparent bioavailability, which reflects how much of the drug was successfully absorbed into the bloodstream, varied significantly. The IM and oral methods displayed moderate to low bioavailability in comparison to the IV method.
- As for absorption rate, the oral administration was the quickest, while the IM injection took the longest time. This variation in absorption rate can have implications towards the suitable selection of administration routes based on specific diagnostic cases and medical urgency.
Plasma Concentrations and Adverse Effects
- The IM method showed extended periods in detectable plasma concentrations. Detectable periods directly impact the effectiveness of the drug as well as considerations for repeated dosages.
- Although considered more practical, the oral administration did not give rise to any serious adverse effects under the single-dose experimental conditions applied during the research.
General Findings and Recommendations
- Based on the susceptibility information derived for human and canine isolates, the researchers suggest a daily oral administration of 10 mg/kg rifampin in the horse’s feed to manage gram-positive bacterial pathogens.
- For more resistant gram-negative bacteria, higher doses (equal to or more than 25 mg/kg) or direct IV administration would be needed.
Cite This Article
APA
Burrows GE, MacAllister CG, Beckstrom DA, Nick JT.
(1985).
Rifampin in the horse: comparison of intravenous, intramuscular, and oral administrations.
Am J Vet Res, 46(2), 442-446.
Publication
Researcher Affiliations
MeSH Terms
- Administration, Oral
- Animals
- Biological Availability
- Female
- Half-Life
- Horses / metabolism
- Injections, Intramuscular / veterinary
- Injections, Intravenous / veterinary
- Male
- Rifampin / administration & dosage
- Rifampin / blood
- Rifampin / metabolism
Citations
This article has been cited 2 times.- Pitta DW, Indugu N, Toth JD, Bender JS, Baker LD, Hennessy ML, Vecchiarelli B, Aceto H, Dou Z. The distribution of microbiomes and resistomes across farm environments in conventional and organic dairy herds in Pennsylvania. Environ Microbiome 2020 Dec 9;15(1):21.
- Baptiste KE, Kyvsgaard NC, Ahmed MO, Damborg P, Dowling PM. Is Rifampin (Rifampicin) Essential for the Treatment of Rhodococcus equi Infections in Foals? A Critical Review of the Role of Rifampin. J Vet Pharmacol Ther 2025 Sep;48(5):345-358.
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