60 to 90 percent of people taking opioids develop constipation. They do this by
- reducing peristalsis
- Slow transit allows further removal of water from the digested material.
PO Opioids are more constipating than the other forms of opioids like transdermal.
Fewer than three spontaneous bowel movements per week or issues with defecation in more than 25% of bowel movements can give a clue to the constipation.
Prophylactic use of laxatives like Senna, Polyethylene glycol or Lactulose help in preventing constipation when Opioids are started. Tip to remember: SPL like in Special.
Lactose-intolerant patients should avoid Lactulose.
Fluids, fiber, increased physical activity and squatting posture help move bowels smoothly.
If the conventional laxatives are used but showed no result then dose should be increased or a different laxative than the one already used should be used.
Probiotics can improve chronic constipation.
Do not use Colace if the patient complains of having hard, dry stools.
Manual disimpaction may be required in some in whom there is no bowel movement for a few days.
SQ Methylnaltrexone can be given in Opioid-induced constipation in refractory cases. Needs dose adjustment in renal impairment.
Linaclotide which is approved for the treatment of irritable bowel syndrome and chronic idiopathic constipation.
According to UpToDate, Patients with heart failure (New York Heart Association class III or IV or ejection fraction <50 percent), renal insufficiency (creatinine clearance <60 mL/min/1.73 m2, end-stage liver disease, or preexisting electrolyte abnormalities should not receive phosphate preparations.