Morphine-N-oxide (genomorphine) is an active opioid metabolite of morphine.

However, pretreatment with amiphenazole or tacrine increases the potency of morphine-N-oxide in relation to morphine (intraperitoneally more so than in subcutaneous administration).

[2] Morphine-N-oxide can also form as a decomposition product of morphine outside the body and may show up in assays of opium and poppy straw concentrate.

Codeine and the semi-synthetics such as heroin, dihydrocodeine, dihydromorphine, hydromorphone, and hydrocodone also have equivalent amine oxide derivatives.

Morphine-N-oxide has a DEA ACSCN of 9307 and annual production quota of 655 grams in 2013.