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Home / Equine Research Bank / Vet Ophthalmol / Effect of topical cyclopentolate alone or combined with phen...
Veterinary ophthalmology2021; 24(6); 582-590; doi: 10.1111/vop.12896

Effect of topical cyclopentolate alone or combined with phenylephrine in healthy horses.

Abstract: Evaluate the effect of repeated doses of topical 1% cyclopentolate hydrochloride alone and in combination with topical 2.5% phenylephrine on pupil diameter (PD), tear production (STT-1), intraocular pressure (IOP), digestive function (gut motility and feces production), and heart rate (HR). Methods: Six healthy mares. Methods: In a prospective, randomized, controlled, and crossover design study, the left eye of six healthy mares was administered 0.2 mL of cyclopentolate alone and in combination with 0.2 mL of phenylephrine. The drugs were administered 3 times a day for 1 day, twice a day for 1 day, and then once a day for 2 days, as commonly used in practice. Daily and two days after the last topical drug administration, HR, digestive auscultation, feces production, STT-1, IOP, and PD were recorded. Results: The cyclopentolate alone significantly increased the horizontal and vertical PD of the treated eye from day 2 to day 6 (p < .0001) compared with the baseline value. The combination with topical phenylephrine did not have any additional effect on mydriasis compare with the cyclopentolate alone. The other ocular and digestive parameters were not affected by repeated doses of cyclopentolate alone or combined. Conclusions: Repeated administration of cyclopentolate alone or combined with phenylephrine induce a significant mydriasis for at least 48 h after the last administration in normal horses' eyes, and do not affect STT-1, IOP, digestive function, and HR. The phenylephrine combined with the cyclopentolate did not potentiate the pupil dilation when compared with cyclopentolate alone in healthy horses.
© 2021 American College of Veterinary Ophthalmologists.
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Publication Date: 2021-05-12 PubMed ID: 33982406DOI: 10.1111/vop.12896Google Scholar: Lookup
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  • Journal Article
  • Randomized Controlled Trial
  • Veterinary

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 study explores the impacts of the repeated use of the drug cyclopentolate, both alone and in combination with phenylephrine, on various physiological aspects of healthy horses, such as pupil dilation, tear production, intraocular pressure, digestive function, and heart rate.

Study Methodology

  • The research was a prospective, randomized, and controlled design study. Six healthy mares were included as subjects in the study.
  • The left eye of each mare was administered with either 0.2 ml of cyclopentolate alone, or in combination with 0.2 ml of phenylephrine. The administration schedule followed was thrice a day on the first day, twice on the second day, and once a day for the following two days.
  • After the drug administration, the horses’ heart rate, digestive function, tear production, intraocular pressure, and pupil diameter were observed and measured daily, and also two days post the final application of the drugs.

Study Results

  • The research found that the administration of cyclopentolate alone caused a significant increase in the horizontal and vertical diameter of the pupil from the second day to the sixth day after application.
  • However, using the drug in combination with phenylephrine did not cause an additional, or amplified effect on pupil dilation (mydriasis). This suggests that phenylephrine did not potentiate the effect of cyclopentolate on pupil dilation in healthy horses.
  • In terms of the other ocular and digestive parameters, such as tear production, intraocular pressure, digestive function, and heart rate, repetitive doses of cyclopentolate, whether used independently or in combination with phenylephrine, did not lead to any significant changes.

Conclusion of the Study

  • The research concluded that the repeated use of cyclopentolate, both alone and combined with phenylephrine, causes a significant dilation of the pupil for at least 48 hours after the final administration in healthy horses’ eyes.
  • The application of these drugs did not result in any notable impacts on tear production, intraocular pressure, digestive function, and heart rate. Finally, phenylephrine did not enhance the effect of cyclopentolate on pupil dilation in the studied horses.

Cite This Article

APA
Bessonnat A, Vanore M. (2021). Effect of topical cyclopentolate alone or combined with phenylephrine in healthy horses. Vet Ophthalmol, 24(6), 582-590. https://doi.org/10.1111/vop.12896

Publication

Veterinary ophthalmology
ISSN: 1463-5224
NlmUniqueID: 100887377
Country: England
Language: English
Volume: 24
Issue: 6
Pages: 582-590

Researcher Affiliations

Bessonnat, Amandine
  • Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada.
Vanore, Maria
  • Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada.

MeSH Terms

  • Administration, Topical
  • Animals
  • Cyclopentolate / pharmacology
  • Female
  • Horses
  • Mydriatics / pharmacology
  • Ophthalmic Solutions / therapeutic use
  • Phenylephrine / pharmacology
  • Prospective Studies
  • Pupil

Grant Funding

  • Fonds du Centenaire

References

This article includes 20 references
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Citations

This article has been cited 1 times.
  1. Kowalska ME, Hafezi F, Pot SA, Hartnack S. Medical Management versus PACK-CXL in Dogs with Infectious Keratitis: A Randomized Controlled Trial Protocol.. Animals (Basel) 2022 Oct 20;12(20).
    doi: 10.3390/ani12202862pubmed: 36290247google scholar: lookup
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