Sufentanil (R30730, brand name Sufenta) is a synthetic opioid analgesic drug approximately 5 to 10 times more potent than its parent drug, fentanyl, and 500 times as potent as morphine. Structurally, sufentanil differs from fentanyl through the addition of a methoxymethyl group on the piperidine ring (which is believed to reduce duration of action), and the replacement of the phenyl ring by thiophene. Sufentanil first was synthesized at Janssen Pharmaceutica in 1974.