Multicenter Study

The Bowel Function Index for evaluating constipation in pain patients: definition of a reference range for a non-constipated population of pain patients.

J. Int. Med. Res. 2011 Jan 1;39(1):41-50.
Randomized Controlled Trial

Fixed ratio (2:1) prolonged-release oxycodone/naloxone combination improves bowel function in patients with moderate-to-severe pain and opioid-induced constipation refractory to at least two classes of laxatives.

Curr Med Res Opin. 2014 Nov 1;30(11):2389-96.
Review

Consensus Recommendations on Initiating Prescription Therapies for Opioid-Induced Constipation.

Pain Med. 2015 Dec 1; 16 (12): 2324-37.