A study investigating the treatment of equine squamous gastric disease with long‐acting injectable or oral omeprazole

Background Equine squamous gastric disease (ESGD) is a highly prevalent disease in horses, particularly in elite athletes. Some horses respond slowly, or fail to respond, to the licensed treatment, oral omeprazole (ORLO). Objectives To compare rates of ESGD healing and improvement between ORLO and a long‐acting injectable omeprazole preparation (LAIO). Study design Retrospective clinical study. Methods The case records and gastroscopy images of horses presenting to Rainbow Equine Hospital over a 12‐month period were reviewed, with images being reviewed blind by one of the authors (David Rendle). Treatment responses were compared between horses that received 2 or 4 injections of 4 mg/kg LAIO at weekly intervals, and horses that received ORLO at 4 mg/kg PO SID for 4 weeks. Data were compared using a Mann–Whitney test with post hoc Dunn's test, chi‐squared test or Fisher's exact test. Results Fifty‐six horses met the inclusion criteria: 29 received LAIO and 27 received ORLO. Treatment groups were comparable in terms of signalment and ESGD lesions. There was a difference in rate of healing when LAIO and ORLO treatment groups were compared at 28 days (LAIO‐97%; ORLO‐67%; p  = .005; OR = 14(1.8–158)), but no difference between LAIO at 14 days and ORLO at 28 days (LAIO‐86%; ORLO‐67%; p  = .12; OR = 3.1 (0.9–10)). Five localised and self‐limiting injection site reactions were identified in 3 horses out of 98 injections (5.1%). Main limitations The study was limited by its retrospective nature, absence of randomisation and limited numbers. Conclusions Four weeks of treatment with LAIO resulted in better rates of ESGD healing than 4 weeks of ORLO. Larger more robust studies of LAIO are warranted.