Alvimopan monohydrate is primarily used in the management of postoperative ileus, a condition where the normal movement of the intestines slows down or stops after abdominal surgery. It helps to accelerate the recovery of gastrointestinal function, allowing patients to resume normal bowel movements more quickly. This can reduce the duration of hospital stays and improve overall recovery outcomes. It is specifically designed for short-term use in hospitalized patients who have undergone bowel resection surgery. By selectively blocking opioid receptors in the gut, it counteracts the constipating effects of opioid pain medications without interfering with their pain-relieving properties in the central nervous system.