This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anaesthesia
Least sedative narcotic? 
Select and explain. 
A. Morphine, B. Codeine, C. Papaverine, D. Noscapine
C: Papaverine
Answer: C: Papaverine 
Explanation: C i.e. Papaverine Papaverine is an opioid alkaloid with almost no central effectsQ (i.e. analgesia, sedation, euphoria, anxiolytic, addictive, respiratory depression). It does not suppress intestinal peristalsis, and relieves spasm in aeries. It is used to treat visceral (GI tract, bile duct, ureter) spasm, vasopasm of coronary & cerebral vessels and erectile dysfunction. It can also be used as smooth muscle relaxant in microsurgery, & cryopreservation of blood vessels and as a topical growth factor.