"Opioids" differ from "opiates" in that they are:
Opiods are synthetics while opiates are semi synthetic. Opiods include pethidine,fentanyl,methadone,dextropropoxyphene,tramadol. Semisynthetic opiates include heroin ,pholcodine,ethylmorphine . Ref: KD Tripathi 8th ed.
More powerful in action
More long acting
Synthetic derivatives
Derived directly from opium
Central Nervous system