Efficacy of Omeprazole Powder Paste or Enteric‐Coated Formulation in Healing of Gastric Ulcers in Horses

Background

GastroGard, an omeprazole powder paste formulation, is considered the standard treatment for gastric ulcers in horses and is highly effective. Gastrozol, an enteric‐coated omeprazole formulation for horses, has recently become available, but efficacy data are controversial and sparse.

Objectives

To investigate the efficacy of GastroGard and Gastrozol at labeled doses (4 and 1 mg of omeprazole per kg bwt, respectively, PO q24h) in healing of gastric ulcers.

Animals

40 horses; 9.5 ± 4.6 years; 491 ± 135 kg.

Methods

Prospective, randomized, blinded study. Horses with an ulcer score ≥1 (Equine Gastric Ulcer Council) were randomly divided into 2 groups and treated for 2 weeks each with GastroGard followed by Gastrozol (A) or vice versa (B). After 2 and 4 weeks, scoring was repeated and compared with baseline. Plasma omeprazole concentrations were measured on the first day of treatment after administration of GastroGard (n = 5) or Gastrozol (n = 5).

Results

Compared with baseline (squamous score (A) 1.65 ± 0.11, (B) 1.98 ± 0.11), ulcer scores at 2 weeks ((A) 0.89 ± 0.11, (B) 1.01 ± 0.11) and 4 weeks ((A) 1.10 ± 0.12, (B) 0.80 ± 0.12) had significantly decreased in both groups (P < .001), independent of treatment (P = .7). Plasma omeprazole concentrations were significantly higher after GastroGard compared with Gastrozol administration (AUC_GG = 2856 (1405‐4576) ng/mL × h, AUC_GZ = 604 (430‐1609) ng/mL × h; P = .03). The bioavailability for Gastrozol was 1.26 (95% CI 0.56–2.81) times higher than for GastroGard.

Conclusions and Clinical Importance

Both Gastrozol and GastroGard, combined with appropriate environmental changes, promote healing of gastric ulcers in horses. However, despite enteric coating of Gastrozol, plasma omeprazole concentrations after single labeled doses were significantly higher with GastroGard.     

Prevalence of Gastric Ulcerations in Horses with Colic

The goal of this study was to determine the prevalence of gastric ulcers in horses with acute abdominal crisis (colic) and to examine the temporal effect of hospitalization on ulcer development in equine patients treated for colic. In addition, other factors that may be associated with gastric ulceration were also explored. The study design was a prospective original study incorporating 169 horses that presented to the George D. Widener Hospital for examination. One hundred and twelve horses presenting with the chief complaint of colic were included in the study group, and 57 horses that presented for non-colic or nonemergency complaints were evaluated and included as case controls. Gastroscopy was performed on equine patients presenting with the chief complaint of colic or horses presenting for reasons other than colic (control); mucosal changes were scored 0 to 3. Additionally, horses presenting for colic were gastroscopically evaluated twice during a 5-day period. Medical records were reviewed for history, clinical findings, laboratory results, and treatment. Seventy-six of 112 horses presenting with the chief complaint of colic had gastric ulceration compared with 41 of 57 horses in the control group. There was a significant association between age of the patient and chief complaint (ie, colic vs control) and between breed and chief complaint. There was no association between gastric ulcer score and chief complaint (colic vs control). Thirty-eight of the 112 horses presenting with colic deteriorated in ulcer score while hospitalized. Using a Pearson chi-squared test, there was no statistically significant association between gastric ulceration with age, breed, or sex. Horses with gastric ulceration in the colic group had lower packed cell volumes compared with horses presenting with colic without gastric ulcers, and this was statistically significant (P < .001). The high incidence of gastric ulceration in the study and control groups supports the reports of other investigators that gastric ulcers in horses, no matter the presenting complaint, are widespread. There was a significant association between breed and chief complaint (P = .005); however, breed and outcome of gastric ulceration were not related (Thoroughbreds were the least likely breed to present for colic). Although a trend in increasing gastric ulceration was seen in hospitalized colic patients, it was not statistically significant. This suggests that horses that are hospitalized may be at increased risk for developing gastric ulcers because of stress, feed deprivation, and administration of treatment. Thus, horses that present for colic should be gastroscopically evaluated if clinical signs raise the index of suspicion for gastric ulceration.     

Prevalence of gastric ulcer syndrome in high-level endurance horses

Reasons for performing the study: Equine gastric ulcers syndrome (EGUS) prevalence studies are rare in the endurance horse and none has been carried out to date in horses competing at high level. Objectives: To determine the prevalence of EGUS in high‐level endurance horses. Methods: Thirty endurance horses competing at high level were selected and submitted to 2 gastroscopic examinations. The first gastroscopy was performed during the interseason period, and the second during the competition season within 2–3 days following a ride of 90–160 km. Data related to housing, feeding, training system as well as age, breed and gender were recorded for each horse. Results: The prevalence of squamous gastric ulcers was 48% during the interseason period (mean score 0.85 ± 0.13 on a scale from 0–4) and 93% during the competition season (mean score 1.60 ± 1.15) with a highly significant difference between the seasons (P = 0.001). Most of the lesions were situated in the squamous portion of the stomach but 33.3% of horses showed also glandular lesions. Significant influence of training and performance level on the gastric score (according to the distance of the ride preceding the second gastroscopy) was shown (P = 0.038). There was also a significant influence of housing on the gastric score (P = 0.002) showing higher scores in the horses kept totally on pasture (mean score: 2.14 ± 0.14) vs. horses housed in a mixed environment (stable + pasture, mean score: 1.43 ± 0.17). Both the pastured and (stabled + pastured) groups were receiving a grain supplement but the pastured group received a higher daily starch intake, which might explain the higher ulcer prevalence. There was no influence of age, breed or gender on the gastric scores. Conclusions: The high prevalence of gastric lesions observed in this study is probably related to the high level of training and performance of the horses examined compared to the population of horses included in the prior study. Potential relevance: This prevalence of EGUS in high‐level endurance horses is comparable to the prevalence established in racing horses. The equine veterinarians may take into consideration EGUS as a potential cause of poor performance.     

The prevalence and risk factors of oesophageal and nonglandular gastric lesions in Thoroughbred racehorses in Saskatchewan

The objective of this study was to investigate the prevalence, severity and risk factors associated with oesophageal and nonglandular gastric lesions in Thoroughbred racehorses in active training in Saskatoon. Mature Thoroughbred horses (n = 94), stabled at Marquis Downs racetrack in Saskatoon, Saskatchewan, Canada, and trained by different trainers (n = 14) for a minimum of one month were included in the study. Horses were examined by gastroscopy and a lesion grade was assigned for each individual horse. Of the 94 horses, 79 (84%) had nonglandular gastric lesions, 70 (74.5%) had gastric ulcers, giving a prevalence of 74.5%, and 9 out of 94 horses (9.6%) had hyperkeratosis and/or hyperaemia. None of the horses had oesophageal lesions. Gender, age, number of races raced, place obtained in those races, history of lameness, history of medical conditions, and history of medications in a 2 month period prior to the gastroscopic examination were not statistically significant as potential risk factors for the prevalence and severity of nonglandular gastric lesions.     

A comparison of the prevalence of gastric ulceration in feral and domesticated horses in the UK

Equine gastric ulcer syndrome is common in domesticated horses, especially those performing in athletic endeavours. However, the prevalence of equine gastric ulcer syndrome in feral populations of horses is not documented. This study investigated the prevalence and severity of squamous and glandular gastric ulceration in an abattoir population of horses in the UK. Both squamous and glandular ulceration were more prevalent in domesticated horses when compared to the feral horses studied.