Pure opiate antagonists are all of the following
, Nalorphine was the first opiod antagonist introduced in 1951 which could reverse morphine action. Later it was found to have agonistic action or kappa re eptor as well, producing lower ceiling analgesia. It is not used clinically because of dysphoric and psychotomimetic effects. Ref KD Tripathi 8th ed.
Naloxone
Nalorphine
Nalmefene
Naltrexone
Central Nervous system