With the limited ability to cross the blood–brain barrier and reach the μ-opioid receptors of the central nervous system, the clinically undesirable effects of centrally acting opioid antagonists (like reversal of opioid-mediated analgesia) are avoided without affecting the intended blockade of μ-opioid receptors in the gastrointestinal tract.

[4][5] Alvimopan is indicated in people to avoid postoperative ileus following partial large or small bowel resection with primary anastomosis.

The peripheral site of action of alvimopan suggests that such a heightened sensitivity would precipitate gastrointestinal effects beyond dyspepsia.

Thus, interactions are to be expected with known P-glycoprotein inhibitors such as amiodarone, bepridil, diltiazem, ciclosporin, itraconazole, quinine, quinidine, spironolactone, and verapamil.

Activation of these receptors by endogenous or exogenous agonists reduces gastrointestinal motility, and alvimopan blocks this effect.

Like most other peripherally-selective MOR antagonists, such as naloxegel and methylnaltrexone, alvimopan is selective for peripheral receptors because is effluxed by P-glycoprotein, which reduces its ability to cross the blood-brain barrier and affect the central nervous system.