Efficacy of omeprazole paste in the treatment and prevention of gastric ulcers in horses

Abstract

Summary Equine gastric ulcer syndrome (EGUS) is very common among performance horses, with a reported prevalence of approximately 90% in racehorses, and also >50% in foals. Omeprazole, an acid pump inhibitor 5 times more potent than ranitidine, has been used with great success to treat EGUS. This multicentre study of Thoroughbred racehorses with endoscopically verified gastric ulcers was designed to demonstrate the efficacy of an equine oral paste formulation of omeprazole in the treatment and prevention of recurrence of EGUS. Of the 100 horses entered into the study, 25 were sham‐dosed for the full 58 days of the study. The remaining 75 horses all received omeprazole paste, 4 mg/kg bwt/day once daily for 28 days. At Day 28, 25 of treated horses continued on this dosing regimen while 25 received a half dose (2 mg/kg bwt once daily) and 25 horses were sham‐dosed. By Day 28, gastric ulcers were completely healed in 77% of omeprazole‐treated horses, while 92% were significantly (P<0.01) improved. In contrast, 96% of the sham‐dosed horses still had gastric ulcers at Day 28. The improvement was maintained in horses that continued on either a full dose or half dose of omeprazole paste until Day 58. However, in those horses that were removed from omeprazole treatment at Day 28, the incidence and severity of the gastric ulcers at the end of the study were similar to those horses that did not receive the omeprazole paste. This study demonstrates that omeprazole paste, 4 mg/kg bwt per os, once daily, is highly effective in healing gastric ulcers in Thoroughbred racehorses and that either a full dose or half dose of omeprazole paste effectively prevents the recurrence of EGUS. The study also indicates that gastric ulcers in untreated horses did not demonstrate a significant rate of spontaneous healing.

Efficacy of Omeprazole Paste in the Prevention of Gastric Ulcers in 2 Years Old Thoroughbreds

“…Equine gastric ulcer syndrome is present in 70 to 90% of active racehorses [1,15]. Racehorses are usually housed individually in a stall or a small paddock except during training.…”

“…Horses were restrained with a nasal twitch, and the endoscope (VQ-8303A, Olympus, Tokyo, Japan) was inserted into the stomach through the nose. The severity of gastric ulcer was assessed from score 0 to 3 based on Andrews' 4-grade scoring system [1]. Based on the first endoscopic examination, 23 of 85 (27.1%) horses were identified as having gastric ulcers, and among them 20 (23.5%) and 3 (3.6%) ulcers were scored as 1 or 2, respectively ( Table 1).…”

“…Andrews et al reported 76.9% (100/130) prevalence of equine gastric ulcers in racehorses [1]. Among them, 33.8% (44/130), 24.6% (32/130) and 18.5% (24/130) had gastric ulcer scores of 3, 2 and 1, respectively [1].…”

A Comparison Between Omeprazole and a Dietary Supplement for the Management of Squamous Gastric Ulceration in Horses

“…The bioavailability of oral enteric coated omeprazole is variable but unaffected by feeding or fasting [16]. Withdrawal of omeprazole after 56 days of treatment has been reported as resulting in a rapid return of gastric ulceration [15]. However, another study showed only a 20% recurrence rate following withdrawal of omeprazole following 56days treatment [13].…”

“…following 25-56 days of treatment [12][13][14][15]. The bioavailability of oral enteric coated omeprazole is variable but unaffected by feeding or fasting [16].…”