Peripheral acting Mu opioid receptor antagonists in the treatment of the opioid-induced constipation: Review

Abstract

The opioid induced constipation (OIC) is an emerging clinical problems that worsen the patients' quality of life requiring opioids for their pain relief. Many drugs have been launched as Peripheral Acting Mu Opioid Receptor Antagonists o PAMORAs (metylnaltrexone, alvimopam and more recently naloxegol), which antagonize the peripheral effects of opioids without affecting the opioids analgesia. Metylnaltrenone and naloxegol have been licensed for the treatment of CIO, meanwhile alvimopam is approved for the recovery of postoperative ileus after major abdominal surgery. All PAMORAs have shown clinical efficacy but is a matter of debate wich should be their role in the manangement of the CIO. The available information about PAMORAs is reviewed and informed strategy on the use of these drugs is proposed.