Ocfentanil (INN) is an opioid analgesic that is an analogue of fentanyl and was developed in the early 1990s. It is similar to fentanyl in effects, producing strong analgesia and sedation, but is slightly more potent, with 3μg/kg of ocfentanil being equivalent to 5μg/kg of fentanyl.

Side effects of fentanyl analogues are similar to those of fentanyl, and include itching, nausea and potentially serious respiratory depression which can be life-threatening.