Candrilli SD, Davis KL, Iyer S. Impact of constipation on opioid use patterns, health care resource utilization, and costs in cancer patients on opioid therapy. J Pain Palliat Care Pharmacother. 2009 Sep 1;23(3):231-41.
Hutchison RW, Anastassopoulos K, Vallow S, Mordin M, Olson W, Hewitt D, Sikirica V. Intravenous patient-controlled analgesia pump and reservoir logistics: results from a multicenter questionnaire. Hosp Pharm. 2007 Nov 1;42(11):1036-44.