“Opioids are a class of substances that inhibit the transmission of painful stimuli [1]. They are characterized by a strong analgesic effect. Opioids may be legally prescribed in the form of opiates such as codeine, morphine, semisynthetic opioids such as oxycodone, synthetic opioids such as fentanyl [2], and there are also illegal forms such as heroin
In the United States, from 1999 to 2019, opioid overdose, either regularly prescribed or illegally acquired, was the cause of death for nearly 500,000 people. In addition to this pronounced mortality burden that has increased gradually over time, opioid overdose has significant morbidity with severe risks and side effects. As a result, opioid misuse is a cause for concern and is considered an epidemic”

National Library of Medicine – NIH (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9517221/)