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Equine veterinary journal2013; 46(4); 416-421; doi: 10.1111/evj.12191

A comparison of two doses of omeprazole in the treatment of equine gastric ulcer syndrome: a blinded, randomised, clinical trial.

Abstract: Studies on omeprazole have reported that doses as low as 0.7 mg/kg bwt per os are potent suppressors of acid production. Yet, to date, no studies have compared treatment efficacy of different doses in clinical cases of equine gastric ulceration. Furthermore, no studies have been performed to compare the healing response of the squamous and glandular mucosa to acid suppression therapy. Objective: To compare: 1) the efficacy of 2 doses of omeprazole in the treatment of primary squamous and glandular gastric ulceration; and 2) the healing response of primary squamous and glandular gastric ulceration to acid suppression therapy. Methods: A blinded, randomised, dose-response clinical trial. Methods: Twenty Thoroughbred racehorses with grade ≥2/4 glandular ulceration were identified on gastroscopy. Seventeen horses also had grade ≥2/4 squamous ulceration. Horses were randomly assigned to one of 2 groups. Horses received either 2.0 g (high dose: 4.0 mg/kg bwt) or 0.8 g (low dose: 1.6 mg/kg bwt) of oral omeprazole per os once daily. Gastroscopy was repeated at 28-35 days. Results: Time and dose significantly affected grades of squamous (P<0.0001, P = 0.02) and glandular (P = 0.006 and 0.005) ulceration. Data analysis did not support our hypothesis that the lower dose would have similar effects (i.e. be noninferior) to the higher dose when considering ulcer healing and ulcer improvement. Improvement was more likely with the high dose for the squamous (P = 0.05) but not glandular (P = 0.4) mucosa. The percentage of glandular ulcers that improved was less than squamous ulcers (P = 0.02). Conclusions: The results suggest that a dose-response exists for the treatment of both squamous and glandular ulcers. Improvement of glandular ulcers was not as complete as observed with squamous ulcers and current equine gastric ulcer syndrome treatment recommendations may not be appropriate for glandular disease.
Publication Date: 2013-11-24 PubMed ID: 24102898DOI: 10.1111/evj.12191Google Scholar: Lookup
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  • Journal Article
  • Randomized Controlled Trial

Summary

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This study investigates the efficacy of two different doses of omeprazole in treating equine gastric ulcers. The findings reveal that a higher dose was more effective for the treatment of both types of ulcers, though improvement of glandular ulcers wasn’t as substantial as that of squamous ulcers.

Research Context

  • Omeprazole is known to be a potent suppressor of acid production, a key mechanism in the formation of gastric ulcers. Earlier studies produced promising results with doses as low as 0.7 mg/kg body weight (bwt).
  • No prior research, however, compared the treatment effectiveness of different doses on clinical cases of equine gastric ulceration, nor analyzed the healing response of both glandular and squamous mucosa to acid suppression therapy.

Study Design

  • The researchers carried out a blinded, randomized, dose-response clinical trial featuring twenty Thoroughbred racehorses with grade ≥2/4 glandular ulceration. Seventeen of these horses also had grade ≥2/4 squamous ulceration.
  • The horses were randomly assigned to one of two groups. They were treated with either 2.0 g (high dose) or 0.8 g (low dose) of oral omeprazole per day.
  • The condition of the horses was reevaluated with gastroscopy after 28-35 days of treatment.

Results

  • The researchers found that time and dosage had a significant effect on grades of both squamous and glandular ulceration. The analysis did not support the hypothesis that the lower dose would yield similar healing and ulcer improvement as the higher dose.
  • The improvement was more pronounced with the higher dose for squamous, but not glandular, ulcers. The rate of improvement of glandular ulcers was comparatively less than that of squamous ulcers.

Conclusions

  • The findings suggest that a dose-response relationship exists for the treatment of both types of ulcers with omeprazole. This means that treatment outcomes are dependent on the dose administered, with larger doses providing better improvement.
  • However, the less satisfactory response of glandular ulcers suggests that they may require different treatment approaches than those currently recommended for equine gastric ulcer syndrome.

Cite This Article

APA
Sykes BW, Sykes KM, Hallowell GD. (2013). A comparison of two doses of omeprazole in the treatment of equine gastric ulcer syndrome: a blinded, randomised, clinical trial. Equine Vet J, 46(4), 416-421. https://doi.org/10.1111/evj.12191

Publication

ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 46
Issue: 4
Pages: 416-421

Researcher Affiliations

Sykes, B W
  • BW Sykes Consultancy, Upper Orara, New South Wales, Australia.
Sykes, K M
    Hallowell, G D

      MeSH Terms

      • Animals
      • Anti-Ulcer Agents / administration & dosage
      • Anti-Ulcer Agents / therapeutic use
      • Dose-Response Relationship, Drug
      • Female
      • Horse Diseases / drug therapy
      • Horses
      • Male
      • Omeprazole / administration & dosage
      • Omeprazole / therapeutic use
      • Stomach Ulcer / drug therapy
      • Stomach Ulcer / veterinary

      Citations

      This article has been cited 17 times.
      1. Frippiat T, Bonhomme M, Dyson S, Votion DM. Evaluation of Owner-Reported Clinical Signs and Fecal Occult Blood Tests as Predictors of Equine Gastric Ulcer Syndrome in Competition Dressage Horses. J Vet Intern Med 2025 Nov-Dec;39(6):e70248.
        doi: 10.1111/jvim.70248pubmed: 41055229google scholar: lookup
      2. Irving J, Pineau V, Shultz S, Ter Woort F, Julien F, Lambey S, van Erck-Westergren E. Impact of Low-Starch Dietary Modifications on Faecal Microbiota Composition and Gastric Disease Scores in Performance Horses. Animals (Basel) 2025 Jun 28;15(13).
        doi: 10.3390/ani15131908pubmed: 40646806google scholar: lookup
      3. Zhang WW, Wang XF, Yu HY, Wang LF. Influence of a diet meal plan on pepsinogen I and II, gastrin-17, and nutritional status in gastric ulcer patients. World J Clin Cases 2024 Jul 26;12(21):4574-4581.
        doi: 10.12998/wjcc.v12.i21.4574pubmed: 39070811google scholar: lookup
      4. Shan R, Steel CM, Sykes B. The Impact of Two Recommended Withholding Periods for Omeprazole and the Use of a Nutraceutical Supplement on Recurrence of Equine Gastric Ulcer Syndrome in Thoroughbred Racehorses. Animals (Basel) 2023 May 31;13(11).
        doi: 10.3390/ani13111823pubmed: 37889700google scholar: lookup
      5. Vokes J, Lovett A, Sykes B. Equine Gastric Ulcer Syndrome: An Update on Current Knowledge. Animals (Basel) 2023 Apr 5;13(7).
        doi: 10.3390/ani13071261pubmed: 37048517google scholar: lookup
      6. Perricone V, Sandrini S, Irshad N, Comi M, Lecchi C, Savoini G, Agazzi A. The Role of Yeast Saccharomyces cerevisiae in Supporting Gut Health in Horses: An Updated Review on Its Effects on Digestibility and Intestinal and Fecal Microbiota. Animals (Basel) 2022 Dec 9;12(24).
        doi: 10.3390/ani12243475pubmed: 36552396google scholar: lookup
      7. Pratt SL, Bowen M, Hallowell GH, Shipman E, Bailey J, Redpath A. Does lesion type or severity predict outcome of therapy for horses with equine glandular gastric disease? - A retrospective study. Vet Med Sci 2023 Jan;9(1):150-157.
        doi: 10.1002/vms3.1034pubmed: 36495212google scholar: lookup
      8. Pratt S, Bowen I, Hallowell G, Shipman E, Redpath A. Assessment of agreement using the equine glandular gastric disease grading system in 84 cases. Vet Med Sci 2022 Jul;8(4):1472-1477.
        doi: 10.1002/vms3.807pubmed: 35412651google scholar: lookup
      9. Hwang H, Dong HJ, Han J, Cho S, Kim Y, Lee I. Prevalence and treatment of gastric ulcers in Thoroughbred racehorses of Korea. J Vet Sci 2022 Mar;23(2):e19.
        doi: 10.4142/jvs.21247pubmed: 35187877google scholar: lookup
      10. Gough S, Hallowell G, Rendle D. Evaluation of the treatment of equine glandular gastric disease with either long-acting-injectable or oral omeprazole. Vet Med Sci 2022 Mar;8(2):561-567.
        doi: 10.1002/vms3.728pubmed: 35167731google scholar: lookup
      11. Hewetson M, Tallon R. Equine Squamous Gastric Disease: Prevalence, Impact and Management. Vet Med (Auckl) 2021;12:381-399.
        doi: 10.2147/VMRR.S235258pubmed: 35004264google scholar: lookup
      12. Wise JC, Hughes KJ, Edwards S, Jacobson GA, Narkowicz CK, Raidal SL. Pharmacokinetic and pharmacodynamic effects of 2 registered omeprazole preparations and varying dose rates in horses. J Vet Intern Med 2021 Jan;35(1):620-631.
        doi: 10.1111/jvim.15971pubmed: 33340169google scholar: lookup
      13. Wise JC, Wilkes EJA, Raidal SL, Xie G, Crosby DE, Hale JN, Hughes KJ. Interobserver and intraobserver reliability for 2 grading systems for gastric ulcer syndrome in horses. J Vet Intern Med 2021 Jan;35(1):571-579.
        doi: 10.1111/jvim.15987pubmed: 33284465google scholar: lookup
      14. Gough S, Hallowell G, Rendle D. A study investigating the treatment of equine squamous gastric disease with long-acting injectable or oral omeprazole. Vet Med Sci 2020 May;6(2):235-241.
        doi: 10.1002/vms3.220pubmed: 31945806google scholar: lookup
      15. Banse HE, Andrews FM. Equine glandular gastric disease: prevalence, impact and management strategies. Vet Med (Auckl) 2019;10:69-76.
        doi: 10.2147/VMRR.S174427pubmed: 31406687google scholar: lookup
      16. Sykes BW, Hewetson M, Hepburn RJ, Luthersson N, Tamzali Y. European College of Equine Internal Medicine Consensus Statement--Equine Gastric Ulcer Syndrome in Adult Horses. J Vet Intern Med 2015 Sep-Oct;29(5):1288-99.
        doi: 10.1111/jvim.13578pubmed: 26340142google scholar: lookup
      17. Sykes BW, Sykes KM, Hallowell GD. Administration of trimethoprim-sulphadimidine does not improve healing of glandular gastric ulceration in horses receiving omeprazole: a randomised, blinded, clinical study. BMC Vet Res 2014 Aug 23;10:180.
        doi: 10.1186/s12917-014-0180-0pubmed: 25927827google scholar: lookup