It was first reported in 1915, and this was followed by the clinical introduction of nalorphine ( N-allylnor " morphine " ) in 1954, naloxone ( N-allyl " oxymorphone " ) in 1960, and naltrexone ( N-methylcyclopropyloxymorphone ) in 1963.
12.
These drugs range from 25 % the analgesic strength of codeine ( or slightly more than 2 % of the strength of morphine ) to several thousand times the strength of morphine, to powerful opioid antagonists, including naloxone ( Narcan ), naltrexone ( Trexan ), diprenorphine ( M5050, the reversing agent for the Immobilon dart ) and nalorphine ( Nalline ).
