title: Methylnaltrexone for the treatment of opioid-induced constipation.
abstract: Opioids are the drugs of choice for treating moderate-to-severe pain, especially for patients in the end stage of cancer or other advanced illnesses, and also in critical care or for the treatment of chronic pain. Side effects such as nausea, pruritus, dizziness and constipation have to be controlled in order to use these drugs to their full potential. Opioid-induced bowel syndrome and constipation caused by activation of μ-receptors in the gut can have such distressing effects that some patients prefer to forego adequate pain control. Methylnaltrexone is a μ-opioid receptor antagonist that, unlike naltrexone or naloxone, does not pass the blood-brain barrier, and therefore does not impair the centrally mediated analgesic effect of opioids. It is licensed for the treatment of opioid-induced constipation in palliative care in more than 50 countries. This article presents practically relevant pharmacological data, basic research results and evidence from clinical research about methylnaltrexone, and outlines potential future therapeutic options for this promising drug.
authors.affiliation: Department of Palliative Care, University Medical Center Freiburg, Robert-Koch-Str. 3, D-79106 Freiburg, Germany. sabine.bader@usz.ch
authors.forename: Sabine
authors.initials: S
authors.lastname: Bader
authors.forename: Thorsten
authors.initials: T
authors.lastname: Dürk
authors.forename: Gerhild
authors.initials: G
authors.lastname: Becker
mesh_terms: D000701:Analgesics, Opioid / Q000009:adverse effects*; D003248:Constipation / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D006801:Humans; D009270:Naloxone / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D009292:Narcotic Antagonists / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D010146:Pain / Q000188:drug therapy* / Q000378:metabolism; D010166:Palliative Care; D000644:Quaternary Ammonium Compounds / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use; D017450:Receptors, Opioid, mu / Q000187:drug effects / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D000644:Quaternary Ammonium Compounds; D017450:Receptors, Opioid, mu; D009270:Naloxone; C041269:N-methylnaloxone