The goal of this clinical trial is to evaluate if intensified omeprazole therapy can reduce high-output stoma (HOS) in adults undergoing ileostomy formation surgery. The main objectives of the study are: * To assess if intensified omeprazole treatment significantly reduces mean daily ileostomy output (ml/24h) during the first three postoperative days compared to standard omeprazole treatment. * To evaluate the proportion of patients meeting the criteria for high-output stoma (HOS ≥1400 ml/day) on consecutive postoperative days. * To measure the time required for stabilization of ileostomy output (\<1400 ml/day maintained for three consecutive days). * To determine the incidence of dehydration-related complications, specifically electrolyte disturbances (hyponatremia, hypokalemia). * To compare the length of initial hospital stay, frequency of rehospitalizations within 30 days post-discharge, and total length of hospital stay (including rehospitalizations). Researchers will compare 10 days intensified omeprazole treatment (loading dose of 80 mg IV followed by 40 mg IV twice daily) with standard treatment (40 mg IV once daily) to determine the effectiveness of intensified dosing in reducing ileostomy output and improving postoperative outcomes. Participants will: * Receive either standard or intensified intravenous omeprazole during their hospitalization and after discharge for 10 days combined. * Undergo daily measurements of ileostomy output. * Have routine laboratory assessments of electrolyte levels. * Participate in follow-up assessments up to 30 days post-discharge, conducted either through outpatient visits or telephone consultations.