Opioid combination: rationale and possible clinical applications

The aim of this review is to provide a potential benefit of an opioid combination at receptor sites, based on experimental data and preliminary clinical studies where a combination of opioids with different characteristics yielded greater analgesic activity with lesser adverse effects. The receptor activity, including intrinsic activity, endocytosis, and oligomerization, and the interaction on opioid receptors and between different opioid receptors or different sites are described. Finally, Clinical observations of opioid combinations reported in literature regarding the possible benefits of such an approach are presented.