Efecto de dos niveles de dosis intravenosas de omeprazol sobre el pH del jugo gástrico de caballos sanos Efeito de dois níveis de doses intravenosas de omeprazol no suco gástrico pH cavalos saudáveisJhon D Ruiz * , MV, MSc, PhD; Juan E Ramírez, MVZ; Ángel Lezcano MVZ. Zootecnia, Universidad CES. Medellin, Colombia. (Received: March 29, 2015; accepted: June 8, 2016) doi: 10.17533/udea.rccp.v29n4a05 Summary Background: omeprazole suppresses gastric acid secretion and increases gastric juice pH by blocking the H+, K+ ATPase in the secretory membrane of parietal cells. Gastric juice pH below 4, long periods of no feed intake and stress are factors predisposing to gastric ulcers in horses. Objective: to determine the effect of 1 and 2 mg/Kg intravenous (IV) omeprazole on the gastric juice pH of Colombian Creole horses. Methods: seven horses were treated with two IV levels of omeprazole (1, and 2 mg/Kg body weight (BW)) in a crossover design. The omeprazole dose for each animal was reconstituted with 100 ml 0.9% NaCl. Gastric pH was measured using a portable pH-meter in stomach samples collected at time 0 (just before treatment), and 1, 2, 3, 5, 7, 9, 11, and 24 hours post-treatment. Results: the gastric pH at time 0 fluctuated from 1.6 to 3.2 in all horses. Both omeprazole doses (1 and 2 mg/Kg) significantly increased the gastric pH (pH>4.6) from 1 to 11 hours after the treatment. At 24 hours post-treatment, pH of the group treated with 1.0 mg/Kg significantly decreased to 2.8 ± 0.3, but remained elevated at 5.7 ± 0.87 for the group treated with 2 mg/Kg. Conclusion: the study demonstrated that a single IV omeprazole dose of 2 mg/Kg, but not 1 mg/Kg, maintained gastric pH above 4 during 24 hours. Grupo de Investigación en Ciencias (INCA-CES). Facultad de Medicina Veterinaria y