Summary: Opioid-induced bowel dysfunction (OIBD) and opioid-induced constipation (OIC) significantly decrease patientsʼ quality of life (QOL), lead to complications and opioid non-compliance resulting in pain exacerbation. Traditional laxatives are first-line preventive and therapeutic measures, although they display limited efficacy and several adverse effects (AE). Non-pharmacology measures, prokinetics, opioid switch, all have little evidence and do not target OIBD and OIC pathophysiology both associated with activation of predominantly µ-opioid receptors mostly peripherally in the gastrointestinal (GI) tract. A combination of prolonged-release (PR) oxycodone with PR naloxone in one tablet with a ratio of 2:1 is available, although limitations include maximal daily dose of 160 mg/80 mg, respectively, and normal liver function.
Peripherally acting µ-opioid receptor antagonists (PAMORA) block opioid receptors in the GI tract without compromising analgesia as they do not cross the blood-brain barrier. Currently three drugs are available: methylnaltrexone, naloxegol and naldemedine. Effective prevention and treatment of OIC is of paramount importance in patients receiving long-term opioid therapy.