comparison between pre‐ and post exercise administration of omeprazole in the treatment of equine gastric ulcer syndrome: A blinded, randomised, clinical trial

REASONS FOR PERFORMING THE STUDY: A recent study suggested that the duration of acid suppression achieved with once‐daily administration of omeprazole is as short as 12 h and that administration of omeprazole prior to exercise may be superior compared with administration at other times of the day in the treatment of equine gastric ulcer syndrome (EGUS). OBJECTIVES: The primary objective of the study was to investigate whether the administration of omeprazole prior to exercise resulted in better healing of EGUS compared with administration post exercise. A secondary objective was to investigate the differences between the response of squamous and glandular EGUS to omeprazole therapy. STUDY DESIGN: A randomised, blinded, clinical trial. METHODS: Twenty‐five horses with grade ≥2/4 squamous EGUS were identified by gastroscopy. The glandular mucosa was also scored. Horses were randomly assigned to receive 4.0 mg/kg bwt of omeprazole per os once daily either 1–4 h prior to high‐intensity exercise (PRE group; 13 horses) or 1–4 h after exercise (POST group; 12 horses). Gastroscopy was repeated at approximately 25 days. RESULTS: No differences were observed between the pre‐ and post exercise treatment groups. Overall, healing was observed in 80% of squamous ulcers vs. 21% of glandular ulcers (P = 0.0002), and improvement was seen in 96% of squamous ulcers vs. 53% of glandular ulcers (P = 0.001). Worsening was observed in the glandular mucosa of 13% of horses. CONCLUSIONS: The results of this study suggest that the timing of administration does not affect ulcer healing. Furthermore, the study demonstrates that the response of glandular ulceration to omeprazole therapy is inferior to that of the squamous mucosa.