Effects of treatment with omeprazole or ranitidine on gastric squamous ulceration in racing Thoroughbreds.
OBJECTIVE
To compare the effects of oral administration of omeprazole and ranitidine on gastric squamous ulceration in Thoroughbreds in race training.


METHODS
Modified crossover study.


METHODS
60 Thoroughbreds in race training with gastric squamous mucosal ulceration.


METHODS
Horses were randomly allocated into 3 groups. Group 1 received no treatment for 28 days followed by administration of omeprazole (4 mg/kg [1.8 mg/lb], PO, once daily) for 28 days; group 2 received omeprazole (4 mg/kg, PO, once daily) for 28 days followed by no treatment for 28 days; and group 3 received ranitidine (6.6 mg/kg [3.0 mg/lb], PO, q 8 h) for 28 days followed by administration of omeprazole (4 mg/kg, PO, once daily) for 28 days. Ulceration was assessed endoscopically at days 0, 28, 42, and 56. Lesions were scored from 0 (no ulceration) to 3 (severe ulceration).


RESULTS
After the initial 28 days of treatment, the decrease in ulcer severity was significantly greater after omeprazole treatment than after ranitidine treatment. Ulcer severity decreased significantly in group 3 horses after 14 days of treatment with omeprazole. Discontinuation of omeprazole resulted in worsening of ulcer scores; however, ulcer scores at completion of the study were less than at day 0. Horses that received omeprazole after 28 days of ranitidine treatment had a further reduction in ulcer severity.


CONCLUSIONS
Omeprazole was more effective than ranitidine in healing gastric squamous ulcers in Thoroughbreds in race training. Improvement was detected by 14 days and persisted in most of the group 2 horses for at least 28 days after omeprazole treatment was discontinued.
Lester
Guy D
GD
School of Veterinary and Biomedical Sciences, Division of Health Sciences, Murdoch University, Western Australia.
Smith
Rachael L
RL
Robertson
Ian D
ID
D000284:Administration, Oral; D000818:Animals; D000897:Anti-Ulcer Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D018592:Cross-Over Studies; D005260:Female; D006734:Horse Diseases / Q000188:drug therapy* / Q000473:pathology; D006736:Horses; D008297:Male; D009853:Omeprazole / Q000008:administration & dosage / Q000627:therapeutic use*; D010805:Physical Conditioning, Animal; D011899:Ranitidine / Q000008:administration & dosage / Q000627:therapeutic use*; D012720:Severity of Illness Index; D013276:Stomach Ulcer / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D013997:Time Factors; D016896:Treatment Outcome
D000897:Anti-Ulcer Agents; D011899:Ranitidine; D009853:Omeprazole