Alvimopan dihydrate is primarily used in the medical field to accelerate the recovery of gastrointestinal function following bowel resection surgery. It is particularly effective in managing postoperative ileus, a common condition where the intestines temporarily lose their ability to move contents along, which can delay recovery and prolong hospital stays. By selectively blocking opioid receptors in the gastrointestinal tract, it helps to counteract the constipating effects of opioid pain medications without interfering with their pain-relieving properties in the central nervous system. This targeted action makes it a valuable tool in enhancing patient recovery and reducing the length of hospital stays after abdominal surgery.