What is Dilaudid? Dilaudid is an opioid narcotic painkiller similar to oxycodone, morphine, methadone, fentanyl, and other narcotic drugs. Buy Dilaudid online.  Dilaudid, like other opioids, arouses receivers on nerves in the brain to increase the threshold to ache and mitigate the perception of ache. Dilaudid is like generic drugs.