U-47700 is an opioid analgesic that acts as a selective agonist of the µ-opioid receptor with a Kd value of 5.3 nM compared to 910 nM for the ?-opioid receptor and has around 7.5 x the potency of morphine in animal models. U-47700 was derived from an earlier opioid AH-7921. U-47700 produce effects similar to those of other potent opioid agonists, including strong analgesia, sedation, euphoria