What are the most addictive narcotics?

OxyContin . Very high on the list in us. When people take narcotics for pain, they are unlikely to become addictive to the drug. However, narcotics gives an intoxicated high when use in high doses. Also powerful anxiety reliever. Dilaudid, heroin, vicodin, Duragesic (fentanyl) other powerful narcotic that induced rapid addiction if use for other reason than pain. Close follow up with physician important.
The fastest acting. The opioids that cross quickest from blood into the brain provide the fastest “reward”. In rough order of what's available in the us: heroin, fentanyl > oxymorphone, oxycodone, hydromorphone > hydrocodone > morphine > codeine. Other properties that make these more desirable is if they come in large milligram doses, easier to separate from the pill binding, and are not mixed with tylenol (acetaminophen).