Treatment of Constipation Without Bowel Obstruction

Initial Assessment and Prevention

The National Comprehensive Cancer Network recommends ruling out bowel obstruction, impaction, and other treatable causes such as hypercalcemia, hypokalemia, hypothyroidism, and diabetes mellitus in patients with constipation without bowel obstruction 1, 2
The National Comprehensive Cancer Network suggests discontinuing any non-essential constipating medications that may be contributing to symptoms in patients with constipation without bowel obstruction 1
Increasing fluid intake and encouraging physical activity when appropriate is recommended for patients with constipation without bowel obstruction by the National Comprehensive Cancer Network and Annals of Oncology 1, 3
The National Comprehensive Cancer Network and Annals of Oncology recommend increasing dietary fiber intake if the patient has adequate fluid intake for patients with constipation without bowel obstruction 1, 3
Ensuring privacy and comfort for defecation, and proper positioning (using a footstool may help) is suggested by Annals of Oncology for patients with constipation without bowel obstruction 3

The National Comprehensive Cancer Network and Annals of Oncology recommend starting with stimulant laxatives such as senna or bisacodyl 10-15 mg daily to TID with a goal of one non-forced bowel movement every 1-2 days for patients with constipation without bowel obstruction 1, 3, 4
Consider adding stool softeners (e.g., docusate) although evidence suggests that stimulant laxatives alone may be sufficient, according to the National Comprehensive Cancer Network 1
Increasing laxative dose as needed to achieve regular bowel movements is recommended by the National Comprehensive Cancer Network 4

The National Comprehensive Cancer Network and Annals of Oncology recommend adding osmotic laxatives such as polyethylene glycol (PEG) 17g with 8 oz water once or twice daily for patients with constipation without bowel obstruction who do not respond to first-line treatment 1, 3
Lactulose 30-60 mL BID-QID is recommended by the National Comprehensive Cancer Network for patients with constipation without bowel obstruction who do not respond to first-line treatment 1, 5
Magnesium hydroxide 30-60 mL daily-BID (use with caution in renal impairment) is suggested by the National Comprehensive Cancer Network and Annals of Oncology for patients with constipation without bowel obstruction who do not respond to first-line treatment 1, 3
For impaction, the National Comprehensive Cancer Network recommends administering glycerine suppositories or mineral oil retention enema, performing manual disimpaction if necessary, and using bisacodyl suppositories (one rectally daily-BID) 1, 5

The National Comprehensive Cancer Network recommends considering adding a prokinetic agent such as metoclopramide 10-20 mg PO QID if gastroparesis is suspected in patients with refractory constipation 1, 2
For opioid-induced constipation (OIC), the National Comprehensive Cancer Network suggests considering peripherally acting μ-opioid receptor antagonists such as methylnaltrexone 0.15 mg/kg subcutaneously every other day (no more than once daily) 1, 2
Naloxegol (for chronic non-cancer pain) is recommended by the National Comprehensive Cancer Network for patients with opioid-induced constipation 2
For chronic idiopathic constipation, the National Comprehensive Cancer Network recommends considering newer agents such as lubiprostone (activates chloride channels to enhance intestinal fluid secretion) and linaclotide (guanylate cyclase-C receptor agonist that enhances intestinal secretions) 2

For elderly patients, Annals of Oncology recommends ensuring access to toilets, especially for patients with decreased mobility, educating patients to attempt defecation at least twice a day, usually 30 minutes after meals, and using PEG (17 g/day) which is particularly safe and effective for elderly patients 3
Avoid liquid paraffin for bed-bound patients due to risk of aspiration, as recommended by Annals of Oncology 3
The National Comprehensive Cancer Network and Annals of Oncology recommend using magnesium salts cautiously in patients with renal impairment due to risk of hypermagnesemia, and avoiding bulk laxatives (e.g., psyllium/Metamucil) as primary therapy for medication-induced constipation 3, 4
Bulk laxatives should be avoided in non-ambulatory patients with low fluid intake due to risk of mechanical obstruction, as recommended by Annals of Oncology 3
Methylnaltrexone should not be used in patients with postoperative ileus or mechanical bowel obstruction, according to the National Comprehensive Cancer Network 2

If no response to initial treatment occurs within 48-72 hours, the National Comprehensive Cancer Network recommends increasing bisacodyl to 10-15 mg two to three times daily 6, 7

The National Comprehensive Cancer Network guidelines suggest that the combination of stimulant and osmotic laxatives is more effective than either agent alone for achieving rapid relief, although the specific combination is not detailed in the provided citations 6, 7
The Gut journal recommends avoiding long-term use of magnesium-based laxatives due to potential toxicity, especially in patients with any degree of renal impairment 8