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Home / Equine Research Bank / Vet Ophthalmol / Ocular penetration of oral doxycycline in the horse.
Veterinary ophthalmology2005; 8(5); 331-335; doi: 10.1111/j.1463-5224.2005.00422.x

Ocular penetration of oral doxycycline in the horse.

Abstract: To investigate intraocular penetration of orally administered doxycycline in the normal equine eye and to compare intraocular and serum doxycycline concentrations. Procedures Six mares were administered doxycycline at 10 mg/kg every 12 h by nasogastric tube for 5 days. Blood, aqueous, and vitreous samples were collected on days 1 and 5. All samples were assayed for doxycycline concentrations. Aqueous and vitreous samples were also assayed for protein quantitation. Results: Doxycycline was rapidly absorbed after the first dose (T(max) value of 1.42 +/- 1.28 h); and elimination of doxycycline occurred slowly (median t(1/2) = 10.88 h). Doxycycline could not be detected in the aqueous on days 1 and 5, nor could it be detected in the vitreous on day 1. On day 5, the mean vitreous doxycycline concentration was 0.17 +/- 0.04 microg/mL at 2 h after drug administration. Conclusions: Repeated oral administration of doxycycline in the horse resulted in steady state serum concentrations of < 1 microg/mL; however, it did not result in appreciable concentrations of drug in the aqueous and vitreous in normal eyes.
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Publication Date: 2005-09-24 PubMed ID: 16178844DOI: 10.1111/j.1463-5224.2005.00422.xGoogle Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article discusses a study on the absorption of the antibiotic doxycycline in the eyes of horses after oral administration, stating that although the drug reaches the blood quickly, it does not significantly penetrate the eyes.

Objectives and Procedures of the Study

  • The study aimed to understand the penetration of the antibiotic doxycycline in the eyes of horses when administered orally. The focus was on comparing the concentration of this drug in the blood (or serum) and in two parts of the equine eye – the aqueous and the vitreous.
  • The experiment involved six adult female horses that were given doxycycline at a dosage rate of 10mg/kg every 12 hours via a nasogastric tube for a period of 5 days.
  • Blood and ocular samples were collected on the first and fifth days of the experiment. These samples were analyzed for concentrations of the doxycycline antibiotic. The ocular samples specifically were also checked for protein quantities.

Findings and Conclusion

  • The results showed that doxycycline was quickly absorbed into the bloodstream, with peak concentrations reached after approximately 1.42 hours following administration. Elimination of the drug was slow, with a median half-life of around 10.88 hours.
  • Despite its quick absorption into the bloodstream, doxycycline could not be detected in the aqueous part of the eye on either the first or the fifth day of the experiment. Additionally, the drug was undetected in the vitreous on the first day, though on the fifth day, a small concentration of doxycycline (around 0.17 micrograms per mL) was found in this section of the eye two hours post-administration.
  • The authors conclude that while repeated oral administration of doxycycline in horses leads to steady concentrations in the serum, it does not result in significant penetration into the aqueous and vitreous parts of their eyes. This suggests that orally-administered doxycycline may not be effective for treating infections or conditions within the equine eye.

Cite This Article

APA
Gilmour MA, Clarke CR, Macallister CG, Dedeo JM, Caudell DL, Morton RJ, Pugh M. (2005). Ocular penetration of oral doxycycline in the horse. Vet Ophthalmol, 8(5), 331-335. https://doi.org/10.1111/j.1463-5224.2005.00422.x

Publication

Veterinary ophthalmology
ISSN: 1463-5216
NlmUniqueID: 100887377
Country: England
Language: English
Volume: 8
Issue: 5
Pages: 331-335

Researcher Affiliations

Gilmour, Margi A
  • Veterinary Clinical Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK, USA. gmargi@cvm.okstate.edu
Clarke, Cyril R
    Macallister, Charles G
      Dedeo, Jacqueline M
        Caudell, David L
          Morton, Rebecca J
            Pugh, Martin

              MeSH Terms

              • Administration, Oral
              • Animals
              • Anti-Bacterial Agents / analysis
              • Anti-Bacterial Agents / blood
              • Anti-Bacterial Agents / pharmacokinetics
              • Aqueous Humor / chemistry
              • Aqueous Humor / metabolism
              • Area Under Curve
              • Biological Availability
              • Doxycycline / analysis
              • Doxycycline / blood
              • Doxycycline / pharmacokinetics
              • Female
              • Horse Diseases / drug therapy
              • Horses / metabolism
              • Uveitis / drug therapy
              • Uveitis / veterinary
              • Vitreous Body / chemistry
              • Vitreous Body / metabolism

              Citations

              This article has been cited 6 times.
              1. Chen SH, Lin YJ, Wang LC, Tsai HY, Yang CH, Teng YT, Hsu SM. Doxycycline Ameliorates the Severity of Experimental Proliferative Vitreoretinopathy in Mice. Int J Mol Sci 2021 Oct 28;22(21).
                doi: 10.3390/ijms222111670pubmed: 34769100google scholar: lookup
              2. Chapuis RJJ, Smith JS, French HM, Toka FN, Peterson EW, Little EL. Nonlinear Mixed-Effect Pharmacokinetic Modeling and Distribution of Doxycycline in Healthy Female Donkeys after Multiple Intragastric Dosing-Preliminary Investigation. Animals (Basel) 2021 Jul 9;11(7).
                doi: 10.3390/ani11072047pubmed: 34359175google scholar: lookup
              3. Caol S, Divers T, Crisman M, Chang YF. In vitro susceptibility of Borrelia burgdorferi isolates to three antibiotics commonly used for treating equine Lyme disease. BMC Vet Res 2017 Sep 29;13(1):293.
                doi: 10.1186/s12917-017-1212-3pubmed: 28962614google scholar: lookup
              4. Rúa O, Larráyoz IM, Barajas MT, Velilla S, Martínez A. Oral doxycycline reduces pterygium lesions; results from a double blind, randomized, placebo controlled clinical trial. PLoS One 2012;7(12):e52696.
                doi: 10.1371/journal.pone.0052696pubmed: 23285154google scholar: lookup
              5. Altan F, Corum O, Durna Corum D, Uney K, Terzi E, Bilen S, Sonmez AY, Elmas M. Pharmacokinetic behaviour and pharmacokinetic-pharmacodynamic integration of doxycycline in rainbow trout (Oncorhynchus mykiss) after intravascular, intramuscular and oral administrations. Vet Med Sci 2024 May;10(3):e1419.
                doi: 10.1002/vms3.1419pubmed: 38520701google scholar: lookup
              6. Suh A, Ong J, Gibson CR, Mader T, Berdahl J, Waisberg E, Lee AG. The evaluation and management of corneal penetrating and perforating injuries during long-duration spaceflight. Eye (Lond) 2024 Jul;38(10):1793-1795.
                doi: 10.1038/s41433-024-02996-4pubmed: 38424146google scholar: lookup
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