Opioid receptors, which are mostly present in the central and peripheral nerve systems as well as the gastrointestinal tract, are the site of action for opioids. Both Opioids somatic and psychotropic effects are mediated by these receptors. The class of medications known as opioids includes partial agonists, such as the anti-diarrhea medicine loperamide, and antagonists, such as naloxegol, which do not pass the blood-brain barrier but can prevent other opioids from attaching to opioid receptors.
The majority of Opioids are prohibited substances because they are addictive and can overdose fatally. Between 28 and 38 million persons took opioids illegally in 2013 (corresponding to 0.6% to 0.8% of all people in the world between the ages of 15 and 65). An estimated 4 million Americans took opioids recreationally or were dependent on them in 2011. As of 2015, the overprescription of opiate painkillers and the low-cost illicit heroin are to blame for rising rates of recreational use and addiction. In contrast, worries about overprescribing, inflated adverse effects, and opiate addiction are also to account for the undertreatment of pain.
