Note that semi-synthetic is a category too that "synthetic opioid" generally excludes. Natural opioids: codeine, morphine. Semi-synthetic opioids: heroin, hyd

Note that semi-synthetic is a category too that "synthetic opioid" generally excludes. Natural opioids: codeine, morphine. Semi-synthetic opioids: heroin, hydromorphone, hydrocodone, oxycodone, etc. Synthetic opioids: methadone (though this is usually excluded from the reporting of "synthetic opioid overdose deaths" for various reasons), demerol, fentanyl, lots of -fentanyl analogs, etc.