A narcotic analgesic that has both agonistic and antagonistic activities on opiate receptor sites is:

a. Morphine
b. Meperedine hydrochloride
c. Butorphanol tartrate (Stadol)
d. Fentanyl

c
Rationale: a. Morphine has agonist properties as it is a true opiate.
b. Merperedine hydrochloride binds to opiate receptors creating an agonist effect.
c. Correct.
d. Fentanyl binds with opiate receptors causing an agonist effect.