Opiates

[SONALI SEN]

Can Anyone Please Explain How Morphine [mechanism Of Action]causes .....gi Effects(constipation),pupil Constriction And Bladder And Ureter Spasms??????

[niharhotchandani]

possibly due to the central actions of morphine... 1. stimulation of the EW nucleus will cause miosis 2. stimulationof the vagal centre will cause the gi effects ... again only possibly!!!

[znazem]

oh pharmacology! my favourite field, hehe.. anyways,

opioids cause constipation because upon administration they're action is based right on the intestines and the cns, this increases the tone & segmentation in the git but slows down propulsive movements in the git, when this tone increases and increases it causes spasms in the git, this can also lead to spams of pyloric, ileocacal and anal sphincters.

since opiods decrease water transfer and electrolytes from mucosa to lumen absorption is increasted from stasis..

..thus patients under administration of opioids remain under chronic constipation