Q: All of the following drugs can be given as epidural Except?

A) Morphine, 

B) Ketamine,

C) Clonidine

D) Lidocaine

E) Propofol

Answer: E (Propofol)

Propofol is obviously can't be given due to risk of sedation and has never been tried! Morphine, Ketamine and Lidocaine are well known to get used as epidulrals. Objective of above question is to bring to attention the use of Clonidine as an epidural.

It is well established that clonidine is an effective analgesic, and this is attributable to its α2-agonist activity. A tremendous amount of modulation of incoming pain signals occurs in the dorsal horn of the spinal cord prior to being sent to higher centers in the CNS. Messages are either strengthened or attenuated by release of various neurotransmitters by primary afferent Aδ or C fibers, interneurons, and descending bulbospinal fibers. Nociceptive stimuli will promote release of excitatory transmitters from primary afferents in the dorsal horn. To compensate, there is simultaneous release of norepinephrine from descending inhibitory bulbospinal neurons, which binds to α2-receptors in the dorsal horn to diminish afferent pain transmission, thereby producing analgesia.