Global Opioid Crisis: Two Sides of the Same Coin

Abstract

All opioid drugs apparently share this common mechanism of action. How-ever, they do not all have the same pharmacokinetics; they do not all undergo the same actions by the body, or even the same pharmacodynamics; they do not all have the same effect on the body. Slight differences in their chemical structure mean that different opioids give rise to different metabolites, bioavailability, dis-tribution, affinity, selectivity and, ultimately, different effectiveness. In addition, the existence of different types and subtypes of receptors (MOR, DOR, KOR, and ORL1), whose expression varies throughout the different tissues and under certain conditions of the cellular environment, contributes to morphine, oxycodone, fen-tanyl, or tramadol having a different analgesic efficacy for different types of pain or pathophysiological conditions. The truth is that, in many cases, there is still no clear criteriaon when to administer one or another opioid, and the physician’s own clinical experience is limiting factor in the choice: medicine based on experience.