The case of biliary duct stricture with retching and vomiting, given 3mg morphine epiduraly daily, one day 12 mg mistakenly dose of epidural, morphine given. Not present:-
Itching
Urinary retention
Increase vomiting
Overstimulation of respiratory centre
Side effect of high dose epidural opioid: Nausea and vomiting Pruritis Urinary retention Respiratory depression High dose of opioid can spread centrally and stimulate CTZ center and can precipitate nausea and vomiting. Pruritis due to morphine is not due to histamine release, high dose morphine can spread centrally, act on trigeminal nerve and cause pruritis. Urinary retention in morphine use is due to it's action on sacral spinal cord, therefore it can happen even at normal dose and not related to high dose. Respiratory depression in morphine overdose due to migration of morphine centrally.