Hydromorphone, also known as Dilaudid, is a potent opioid pain medication used to treat moderate to severe pain. Some synonyms for hydromorphone include: narcotic analgesic, opiate, painkiller, morphinomimetic, and opioid agonist. It is also classified as a Schedule II controlled substance due to its potential for abuse and dependence. Other medications that are similar in their effects on pain relief and classification include oxycodone, fentanyl, and morphine. It is important to use these medications only as directed by a healthcare provider and to be aware of the potential side effects and risks associated with their use.