Opioids / Table 1

TABLE 1. Summary of human behavioral pharmacology abuse liability assessment

	Mu agonists	Mixed agonist-antagonists							Opioid Antagonists
	Morphine and hydromorphone	Buprenorphine	Pentazocine		Butorphanol		Nalbuphine		Naloxone and naltrexone
Subjective and discriminative effects
Nondependent subjects Morphine-like Non-morphine-like^a	Yes No	Yes No		Yes Yes		Some Yes		Some Yes	No No
Physically dependent subjects Morphine-like Withdrawal-like	Attenuated No	Attenuated Variable		No Yes		No Yes		No Yes	No Yes
Antagonist activity
Precipitates withdrawal	No	Variable		Yes		Yes		Yes	Yes
Antagonist/analgesic ratio	Infinite	>26.67		2		0.75		0.3	0
Physical dependence capacity
Suppresses abstinence	Yes	Yes		No		No		No	No
Abstinence syndrome Morphine-like Non-morphine-like^a	Yes No	Mild No		Yes Yes		Yes Yes		Yes Yes	None None
Putative receptor activity Mu Kappa	Agonist None	Partial Ag Antagonist		Partial Ag Ag/partial Ag		Partial Ag Ag/partial Ag		Partial Ag Ag/partial Ag	Antagonist Antagonist
Evidence of abuse	Yes	Yes		Yes, limited		Infrequent		No	No

^a Possibly kappa agonist effects.