Definitions:

1. A narcotic antagonist that counteracts the effects of narcotics, especially the effects of poisoning by morphine. NOUN
   • Nalorphine's ability to produce withdrawal symptoms made it useful in diagnosing opioid dependence.
2. A semisynthetic opioid, used historically to reverse opioid overdose and to test for opioid dependence. NOUN
   • Nalorphine was once used in emergency settings to counteract morphine overdoses.

Synonyms:

• nalline