Review

The endocrine effects of long-term oral opioid therapy: a case report and review of the literature.

J Opioid Manag. 2011 Mar 1;7(2):145-54.
Comparative Study

Chronic methadone treatment shows a better cost/benefit ratio than chronic morphine in mice.

J. Pharmacol. Exp. Ther. 2012 Feb 1;340(2):386-92.
Article

Mechanisms that underlie μ-opioid receptor agonist-induced constipation: differential involvement of μ-opioid receptor sites and responsible regions.

J. Pharmacol. Exp. Ther. 2013 Oct 1;347(1):91-9.