From the Guidelines
Methylnaltrexone is not recommended for routine preventive use after surgery to avoid postoperative ileus, as the current evidence base does not strongly support its efficacy in this context 1. The most effective approach to preventing postoperative ileus involves a multimodal strategy that includes early mobilization, minimally invasive surgical techniques, opioid-sparing analgesia, and early oral feeding. Key considerations in the prevention of postoperative ileus include:
- Optimized fluid management to avoid overloading, which can impair gastrointestinal function 1
- The use of laparoscopic-assisted surgery when possible, as it leads to faster return of bowel function compared to open surgery 1
- Avoidance of nasogastric decompression unless absolutely necessary, as it may prolong the duration of postoperative ileus 1
- Early removal of urinary catheters and nasogastric tubes when possible, to reduce the risk of complications and promote recovery 1
- Consideration of oral magnesium oxide or bisacodyl to promote postoperative bowel function, although evidence is mixed and these should not be relied upon as sole measures 1
- The use of Alvimopan, a peripheral mu-opioid receptor antagonist with FDA approval for accelerating gastrointestinal recovery after bowel resection surgery, may be considered in specific cases, but its use should be guided by the individual patient's risk factors and the surgical procedure undertaken 1. Given the complex pathophysiology of postoperative ileus, which involves inflammatory processes and neural inhibition beyond just opioid effects, targeting only the opioid component with methylnaltrexone may not be sufficient for prevention 1. Therefore, a comprehensive approach that addresses multiple factors contributing to postoperative ileus is preferable to the use of methylnaltrexone alone for preventive purposes.
From the Research
Preventive Use of Methylnaltrexone Post-Op to Avoid Ileus
- The use of methylnaltrexone to prevent postoperative ileus has been studied in several trials 2, 3, 4.
- A study published in 2022 found that methylnaltrexone did not significantly reduce the time to resolution of ileus, length of stay, duration of gastric decompression, or total parenteral nutrition requirements in patients with postoperative ileus 2.
- Another study published in 2011 found that methylnaltrexone did not shorten the duration of postoperative ileus following segmental colectomy, but it was safe and well-tolerated 3.
- A review of the literature published in 2008 discussed the potential role of methylnaltrexone in the treatment of postoperative ileus, but noted that further analyses and clinical trials were needed to determine its efficacy 4.
- Other studies have focused on the management of prolonged post-operative ileus, and have recommended strategies such as regular evaluation and correction of electrolytes, review of analgesic prescription, and nasogastric decompression 5.
- Methylnaltrexone has also been used to treat opioid-induced constipation in critical care patients, and has been shown to improve gastrointestinal function in this population 6.
Efficacy of Methylnaltrexone
- The efficacy of methylnaltrexone in preventing postoperative ileus is unclear, with some studies finding no significant benefit 2, 3.
- However, methylnaltrexone has been shown to be safe and well-tolerated in patients with postoperative ileus 2, 3.
- Further research is needed to determine the potential role of methylnaltrexone in the prevention and treatment of postoperative ileus.
Safety of Methylnaltrexone
- Methylnaltrexone has been shown to be safe and well-tolerated in patients with postoperative ileus 2, 3.
- The most commonly observed adverse events associated with methylnaltrexone are nausea, pyrexia, and vomiting 3.
- Methylnaltrexone has not been associated with an increased risk of gastrointestinal perforations 2.