What is the recommended treatment for narcotic-associated constipation in hospice care?

Management of Narcotic-Associated Constipation in Hospice Care

Start all hospice patients on prophylactic stimulant laxatives (senna or bisacodyl) immediately when initiating opioids, as tolerance to opioid-induced constipation does not develop and it occurs in nearly all patients. 1, 2

Prophylactic First-Line Approach

• Initiate a stimulant laxative such as senna 2 tablets every morning or bisacodyl 10-15 mg daily at the start of opioid therapy, with a goal of one non-forced bowel movement every 1-2 days 1, 2
• Do not use docusate (stool softeners) alone or add them to stimulant laxatives—the NCCN explicitly states docusate has not shown benefit and is not recommended 3, 2
• Discontinue any non-essential constipating medications (antacids, anticholinergics, antiemetics) 1
• Encourage increased fluid intake and physical activity when appropriate for the patient's functional status 1, 4
• Increase the laxative dose when escalating the opioid dose 2

Second-Line Treatment for Persistent Constipation

• Before escalating therapy, rule out fecal impaction and bowel obstruction through physical examination 1, 4
• Assess and treat reversible causes: hypercalcemia, hypokalemia, hypothyroidism, and diabetes mellitus 1, 4
• Add or increase bisacodyl to 10-15 mg two to three times daily 1
• Consider adding osmotic laxatives such as polyethylene glycol (PEG) 17 grams twice daily, lactulose, magnesium hydroxide, or magnesium citrate 1, 3
• Avoid magnesium-based products in patients with renal insufficiency due to hypermagnesemia risk 3
• Never use bulk laxatives like psyllium for opioid-induced constipation—they are ineffective and may worsen symptoms 3, 2

Management of Fecal Impaction

• Administer glycerin suppositories or perform manual disimpaction if impaction is present 1
• Consider rectal bisacodyl suppository once daily for persistent symptoms 1

Third-Line Treatment: Peripherally Acting μ-Opioid Receptor Antagonists (PAMORAs)

• For laxative-refractory constipation, consider methylnaltrexone 0.15 mg/kg subcutaneously every other day (maximum once daily) in hospice patients with advanced illness 1, 5
• Methylnaltrexone induces laxation within 4 hours in 58-62% of patients while preserving opioid analgesia 5, 6
• Do not use methylnaltrexone in patients with mechanical bowel obstruction or postoperative ileus 1, 5
• For hospice patients with moderate to severe renal impairment (creatinine clearance <60 mL/min), reduce the dose to 0.075 mg/kg every other day 5
• Naloxegol 12.5-25 mg once daily is an alternative PAMORA, though primarily studied in chronic non-cancer pain 1, 2

Additional Considerations

• If gastroparesis is suspected, consider adding metoclopramide as a prokinetic agent, though use caution in elderly patients due to tardive dyskinesia risk 1, 2
• Opioid rotation to fentanyl or methadone may be considered as an alternative strategy 2
• Lubiprostone (a chloride channel activator) and linaclotide (a guanylate cyclase-C agonist) are newer agents that can be effective, though they are rarely used in hospice settings 1, 7

Critical Pitfalls to Avoid

• Never delay prophylactic laxatives when starting opioids—waiting for constipation to develop significantly worsens patient quality of life 4, 2
• Do not rely on stool softeners (docusate) alone without stimulant laxatives, as they are clinically ineffective 3, 2
• Always rule out obstruction before escalating to stimulants or PAMORAs to avoid serious complications including bowel perforation 1, 4, 2
• Avoid depending exclusively on lifestyle modifications (fiber, fluids, activity) without pharmacological intervention in advanced disease 4
• Be aware that severe adverse events with methylnaltrexone, including abdominal pain, severe diarrhea, dehydration, and cardiovascular collapse, have been reported 6

Monitoring and Reassessment

• Target one non-forced bowel movement every 1-2 days as the therapeutic goal 1, 2
• If patients do not have a bowel movement for 3 consecutive days, permit rescue laxatives such as bisacodyl tablets (up to 4 tablets orally once in 24 hours) 5
• Regularly reassess bowel function and adjust the treatment regimen as the patient's condition and opioid requirements change 2