Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 522

Opiate pain medications are well known to cause constipation. Chronic opiate use results in constipation in up to 50% of individuals.⁵⁸ Methadone and fentanyl may be less constipating than other morphine derivatives.^59,60 Opiates potently slow gastrointestinal transit and allow enhanced intestinal absorption of fluid. A rational approach involves outlining a strategy to prevent constipation at the initiation of opiate use, although there have been no high‐quality studies to indicate the best strategy. Peripherally acting mu‐opioid receptor antagonists (PAMORAs) reverse opiate‐induced constipation without affecting the analgesic effects or causing withdrawal symptoms (e.g. nalexagol, naldemedine, and methylnaltrexone).^61,62 A systematic review and network meta‐analysis of randomized controlled trials has shown PAMORAs to be superior to placebo in the treatment of opiate‐induced constipation.⁶³ Methylnaltrexone improved stool frequency in opiate‐induced constipation. It is typically reserved for patients with more refractory symptoms as it is administered by injection every other day.⁶⁴ PEG improved stool form in methadone‐induced constipation.⁶⁵ Stimulant laxatives are also commonly used for opiate‐induced constipation.