September 2017 – Opiates cause constipation by several mechanisms:
– Binding intestinal mu receptors and slowing peristalsis
– Delaying gastric emptying
– Increasing anal sphincter tone
– Increasing water and electrolyte reabsorption from slowed peristalsis.
Our experience shows that using a contact cathartic such as senna can counter these effects with excellent results.
We start with 1 tablet of 8.6 mg senna at night and increase slowly up to 4 tabs twice daily to achieve regular BMs.
We add lactulose and other osmotic products as the second line.
We do not find stool softeners to be very effective in this population.
We rarely need to advance to more expensive opioid antagonists for management.