<prompt> True about epidural opioids are all except:Act on dorsal horn substantia gelatinosaCan cause ItchingFunction of the intestine is not affectedCan cause respiratory depression  <response>: Ans. C Function of the intestine is not affectedRef: Katzung 11e p542Because of their direct action on the superficial neurons of the spinal cord dorsal horn, opioids can also be used as regional analgesics by administration into the epidural or subarachnoid spaces of the spinal column.It was initially assumed that the epidural application of opioids might selectively produce analgesia without impairment of motor, autonomic, or sensory functions other than pain. However, respiratory depression can occur after the drug is injected into the epidural space and may require reversal with naloxone.Effects such as pruritus and nausea and vomiting are common after epidural and subarachnoid administration of opioids and may also be reversed with naloxone if necessary.Currently, the epidural route is favored because systemic adverse effects are less common 