Opioid/naloxone prolonged release combinations for opioid induced constipation.

I read with great interest the recent article by Chen et al in a recent issue of your esteemed journal. The article is highly thought provoking. One emerging therapeutic alternative for opioid induced constipation is the emergence of opioid/naloxone prolonged release combinations. For instance, naloxone when administered in a 1:2 ratio with oxycodone reverses the inhibitory effect of oxycodone on the gastrointestinal tract. The advantage of oxycodone/naloxone prolonged release (OXN) is that while its anti-nociceptive efficacy is equivalent to that of oxycodone prolonged release (OXC), it significantly decreases the "Bowel Function Index" thereby ameliorating symptoms of opioid induced constipation to a large extent. Schutter et al in a recent study have reported a decrease in the bowel function index from 38.2 to 15.1. Similarly, Löwenstein et al in another recent study have reported that following a month of therapy, complete spontaneous bowel movements per week is increased from one in OXC therapy to three in OXN therapy.