Which medications in the drug class Peripherally-Acting Mu-Opioid Receptor Antagonists are used in the treatment of Constipation?

Updated: Jul 04, 2019
  • Author: Marc D Basson, MD, PhD, MBA, FACS; Chief Editor: BS Anand, MD  more...
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Peripherally-Acting Mu-Opioid Receptor Antagonists

Peripherally acting mu-opioid receptor antagonists (PAMORAs) may provide relief from GI adverse effects such as constipation associated with chronic opioid use.

Methylnaltrexone (Relistor)

Methylnaltrexone is a PAMORA. It selectively displaces opioids from mu-opioid receptors outside the central nervous system (CNS), including those located in the GI tract, thereby decreasing the constipating effects of opioids. It is indicated for opioid-induced constipation in patients with advanced illness receiving palliative care when response to laxatives has not been sufficient. It is also indicated for opioid-induced constipation in patients with chronic noncancer pain who are treated with opioids. It is available as an injectable solution for subcutaneous use.

Naloxegol (Movantik)

Naloxegol is a PAMORA indicated for opioid-induced constipation in adults with chronic noncancer pain. Antagonism of gastrointestinal mu-opioid receptors by naloxegol inhibits the opioid-induced delay of GI transit time.

Alvimopan (Entereg)

Alvimopan is a peripherally acting mu-opioid receptor antagonist. It binds mu-opioid receptors in the gut, thereby selectively inhibiting the negative opioid effects on GI function and motility. It is indicated for postoperative ileus after bowel resection with primary anastomosis.

In 5 clinical studies that enrolled more than 2500 patients, alvimopan demonstrated accelerated recovery time of upper and lower tract GI function compared with placebo. A decrease in the hospital days was also observed in the alvimopan group.

Alvimopan is only available to hospitals after they complete a registration process designed to maintain the benefits associated with short-term use and prevent long-term outpatient use (Entereg Access Support and Education [EASE] program).

Naldemedine (Symproic)

Opioid antagonist with binding affinities for mu-, delta-, and kappa-opioid receptors. Naldemedine is a derivative of naltrexone to which a side chain has been added that increases the molecular weight and the polar surface area, thereby reducing its ability to cross the blood-brain barrier. It is indicated for opioid-induced constipation in adults with noncancer pain.

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