Managing Incomplete Bowel Emptying After Chemotherapy

Assessment and Diagnosis

The National Comprehensive Cancer Network recommends that constipation assessment should include physical examination, evaluation of medication list for constipating agents, and ruling out treatable causes such as hypercalcemia, hypokalemia, hypothyroidism, and diabetes mellitus 1, 2
Physical examination should include abdominal exam and digital rectal examination to rule out impaction 3
Plain abdominal X-ray may be useful to assess extent of fecal loading and exclude bowel obstruction in severe cases 3, 4

The National Comprehensive Cancer Network recommends stimulant laxatives as first-line therapy, with senna or bisacodyl 10-15 mg, 2-3 times daily, with goal of one non-forced bowel movement every 1-2 days 1, 5
Evidence shows that senna alone is more effective than senna combined with docusate (stool softener) 2, 5
Osmotic laxatives such as polyethylene glycol (PEG) may be added for persistent symptoms, with a dose of 17g (heaping tablespoon) with 8 oz water twice daily 5, 6

For persistent constipation despite first-line measures, consider rectal bisacodyl suppositories once or twice daily, or add a prokinetic agent such as metoclopramide if gastroparesis is suspected 1, 5
Peripherally acting μ-opioid receptor antagonists such as methylnaltrexone 0.15 mg/kg subcutaneously every other day may be used for opioid-induced constipation 1, 5
Lubiprostone or linaclotide may be considered for severe refractory cases 5

Using stool softeners alone without stimulant laxatives is ineffective, and failing to provide prophylactic treatment when starting constipating medications should be avoided 2, 6
Enemas should be avoided in patients with neutropenia or thrombocytopenia, and magnesium-based products should be used cautiously in patients with renal impairment 3, 5