Metopon

Metopon (5-methylhydromorphone hydrochloride) is an opiate analogue that is a methylated derivative of hydromorphone which was invented in 1948 as an analgesic.

Metopon is sometimes used in medicine, but although longer acting than hydromorphone, metopon is less potent and its oral bioavailability, while higher than that of morphine, is still fairly low, so generally metopon has few advantages to distinguish it from other, more commonly used opioid analgesics, although it does have a slightly lower tendency to produce nausea and respiratory depression compared to morphine.

CAS number 124-92-5 (Metopon hydrochloride)