Metopon

Metopon (5-methyldihydromorphone) is an opiate analogue that is a methylated derivative of hydromorphone which was invented in 1929 as an analgesic.

Metopon is sometimes used in medicine, although longer acting than hydromorphone, Metopon is less potent and its oral bioavailability is fairly low. 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.