14-Phenylpropoxymetopon (PPOM) is an opiate analogue that is a derivative of metopon which has been substituted with a γ-phenylpropoxy group at the 14-position. It is a highly potent analgesic drug several thousand times stronger than morphine, with a similar in vivo potency to etorphine. The 14-phenylpropoxy substitution appears to confer potent μ-opioid agonist activity, even when combined with substitutions such as N-cyclopropyl or N-allyl, which normally result in μ-opioid antagonist compounds.