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Equine veterinary journal2003; 35(5); 484-490; doi: 10.2746/042516403775600415

Pharmacokinetics of fentanyl following intravenous and transdermal administration in horses.

Abstract: Although fentanyl has been reported to cause CNS excitation in horses, a transdermal therapeutic system (TTS) containing this mu agonist has recently been used empirically in equine medicine to treat moderate to severe pain. A better understanding of the disposition of fentanyl following transdermal administration would facilitate the clinical use of TTS fentanyl to obtain analgesia in horses. Objective: To determine the pharmacokinetics of fentanyl following i.v. and TTS patch administration in healthy, mature horses and to evaluate the tolerance of horses to TTS fentanyl administration. Methods: The pharmacokinetics of fentanyl in serum were assessed following a single i.v. dose, a single TTS dose, and multiple TTS doses in 6 healthy horses. Physical examinations, haematology and serum biochemistry analyses during transdermal fentanyl application were then performed to determine tolerance of continuous fentanyl administration. Results: Fentanyl was very rapidly and completely absorbed following a single TTS dose. Mean serum fentanyl concentrations consistent with analgesia in other species were reached by 1 h and maintained until 32 h after patch application. Similar steady state serum concentrations were obtained when multiple doses of TTS fentanyl were administered every 48 or 72 h over 8 or 9 days, with less fluctuation in serum concentrations during the 48 h dosing interval. Three horses exhibited brief (< 12 h) episodes of increased body temperature; however, transdermal fentanyl administrations were not associated with other significant changes in haematology and biochemistry panels or physical examination findings. Conclusions: Although the pharmacodynamics of fentanyl have not been investigated fully in horses, transdermally-administered fentanyl exhibited a favourable pharmacokinetic profile without clinically relevant side effects and may be a useful analgesic in equine patients.
Publication Date: 2003-07-24 PubMed ID: 12875327DOI: 10.2746/042516403775600415Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

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The research paper investigates the effect of administering the painkiller fentanyl, intravenously and through a patch, in horses. It concludes that transdermally-administered fentanyl displays favourable pharmacokinetic outcomes without significant side effects, potentially making it a useful tool for treating equine pain.

Objective of the Study

  • The study aimed to understand the disposition of fentanyl in horses administered through a patch and intravenously. Understanding the pharmacokinetics of fentanyl would assist in its clinical use to treat moderate to severe pain in horses.
  • Further, it also aimed to assess the tolerance of horses to fentanyl administration through a transdermal therapeutic system (TTS).

Methodology

  • For this study, six healthy, mature horses were selected and the pharmacokinetics of fentanyl in their serum were studied following a single intravenous dose, a single patch dose, and multiple patch doses.
  • Subsequent physical examinations, hematological and serum biochemical analyses were performed during the TTS fentanyl application to ascertain the tolerance for continuous fentanyl administration in horses.

Results of the Study

  • Fentanyl was absorbed rapidly and thoroughly after a single transdermal dose. It reached serum concentrations that are normally consistent with analgesia (pain relief) in other species within one hour, and these were maintained until 32 hours after the patch application.
  • When multiple doses of fentanyl via TTS were administered, similar steady serum concentrations were achieved over 8 or 9 days, with less fluctuation noted during a 48-hour dosing interval compared to a 72-hour interval.
  • Despite three horses showing brief episodes of elevated body temperature, continuous TTS fentanyl administration was not associated with significant changes in hematological and biochemical panels or physical examination findings.

Conclusions

  • Despite not having fully investigated fentanyl’s pharmacodynamics in horses, the study’s results suggested that transdermally-administered fentanyl offers a favourable pharmacokinetic profile.
  • The lack of clinically significant side effects from its administration indicates that fentanyl may serve as a useful analgesic tool for treating pain in equine patients.

Cite This Article

APA
Maxwell LK, Thomasy SM, Slovis N, Kollias-Baker C. (2003). Pharmacokinetics of fentanyl following intravenous and transdermal administration in horses. Equine Vet J, 35(5), 484-490. https://doi.org/10.2746/042516403775600415

Publication

ISSN: 0425-1644
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 35
Issue: 5
Pages: 484-490

Researcher Affiliations

Maxwell, L K
  • K. L. Maddy Equine Analytical Chemistry Laboratory, School of Veterinary Medicine, University of California, Davis, California 95616, USA.
Thomasy, S M
    Slovis, N
      Kollias-Baker, C

        MeSH Terms

        • Administration, Cutaneous
        • Analgesics, Opioid / administration & dosage
        • Analgesics, Opioid / blood
        • Analgesics, Opioid / pharmacokinetics
        • Animals
        • Area Under Curve
        • Cross-Over Studies
        • Dose-Response Relationship, Drug
        • Drug Administration Routes / veterinary
        • Drug Administration Schedule / veterinary
        • Female
        • Fentanyl / administration & dosage
        • Fentanyl / blood
        • Fentanyl / pharmacokinetics
        • Horses / blood
        • Horses / metabolism
        • Injections, Intravenous / veterinary
        • Male
        • Pain / drug therapy
        • Pain / veterinary

        Citations

        This article has been cited 4 times.
        1. Dmitrović P, Vanaga J, Dupont J, Franck T, Gougnard A, Detilleux J, Kovalcuka L, Salciccia A, Serteyn D, Sandersen C. Effect of Fentanyl Infusion on Heart Rate Variability and Anaesthetic Requirements in Isoflurane-Anaesthetized Horses. Animals (Basel) 2021 Oct 9;11(10).
          doi: 10.3390/ani11102922pubmed: 34679943google scholar: lookup
        2. Salyards GW, Lemoy MJ, Knych HK, Hill AE, Christe KL. Pharmacokinetics of a Novel, Transdermal Fentanyl Solution in Rhesus Macaques (Macaca mulatta). J Am Assoc Lab Anim Sci 2017 Jul 1;56(4):443-451.
          pubmed: 28724494
        3. Paranjape VV, Knych HK, Berghaus LJ, Giancola S, Cathcart J, Reed RA. Plasma concentrations of buprenorphine administered via matrix-type transdermal patches applied at three different anatomical locations in healthy adult horses. Front Pain Res (Lausanne) 2024;5:1390322.
          doi: 10.3389/fpain.2024.1390322pubmed: 38962712google scholar: lookup
        4. Reed RA, Berghaus LJ, Reynolds RM, Holmes BT, Krikorian AM, Sakai DM, Ishikawa Y, Knych HK. The pharmacokinetics and pharmacodynamics of fentanyl administered via transdermal patch in horses. Front Pain Res (Lausanne) 2024;5:1373759.
          doi: 10.3389/fpain.2024.1373759pubmed: 38571562google scholar: lookup