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

• Succeed was noninferior to omeprazole for resolution of ulceration after 90 days.
• Omeprazole and Succeed significantly reduced ulcer scores at days 30 and 60.
• After 90 days of treatment, the efficacy of omeprazole appeared to be reduced.

Although several studies have assessed the short-term effect of dietary supplements on the treatment and prevention of gastric ulceration in horses, few have assessed the response over a duration of more than 30 days. A blinded randomized noninferiority clinical trial was conducted using 42 Thoroughbred horses in race training with squamous ulceration of ≥ grade 2/4, randomly assigned to one of two treatment groups for a period of 90 days: omeprazole at the full label dose of 4 mg/kg or the Succeed digestive conditioning supplement. Noninferiority analyses and Wilcoxon sign rank tests were used to analyze the data. At day 90, Succeed was noninferior to 4 mg/kg omeprazole administered daily in terms of the proportion of horses with complete resolution of squamous ulceration. At day 30, Succeed was found to be inferior to omeprazole in terms of the proportion of horses with grade ≤1/4 squamous ulceration. The proportion of horses with reducing squamous ulcer score (compared with day 0) was statistically significant for both treatments at days 30 and 60. At day 90 of the 17 horses on Succeed, nine had a reducing squamous ulcer score (P value = .049), and of the 19 horses on omeprazole, 10 had a reducing squamous ulcer score at day 90 (P value = .091). The noninferiority of Succeed compared to omeprazole at 90 days for the complete resolution of squamous ulceration and the reduced efficacy of omeprazole following 90 days of treatment are likely to be of interest to practitioners managing gastric ulceration in performance horses.