Bowel Regimen for Gastroparesis
Patients with gastroparesis who develop constipation should be treated prophylactically with a stimulating laxative (such as senna or bisacodyl) to increase bowel motility, with the addition of a prokinetic agent like metoclopramide if gastroparesis is contributing to the constipation. 1
Understanding the Problem
Constipation in gastroparesis patients presents a unique challenge because the underlying motility disorder affects the entire gastrointestinal tract, not just the stomach. The delayed gastric emptying that defines gastroparesis often coexists with slow colonic transit, creating a compounded problem. 1
Key contributing factors to address:
- Medications that worsen constipation (anticholinergics, opioids, tricyclic antidepressants) should be discontinued when possible 1
- Diabetic patients require optimized glycemic control, as hyperglycemia worsens both gastroparesis and constipation 2
- Assess for treatable causes including hypercalcemia, hypokalemia, hypothyroidism, and diabetes mellitus 1
Recommended Bowel Regimen Algorithm
First-Line Prophylactic Approach
Start with a stimulating laxative to increase bowel motility: 1
- Senna (preferred based on evidence showing docusate addition is unnecessary) 1
- Bisacodyl 10-15 mg, 2-3 times daily with a goal of one non-forced bowel movement every 1-2 days 1
Important caveat: A small study demonstrated that senna alone was as effective as senna-docusate combination, suggesting stool softeners may not be necessary as first-line agents. 1 However, stool softeners can be added if needed based on stool consistency.
When Gastroparesis Contributes to Constipation
Add a prokinetic agent: 1
- Metoclopramide 10 mg three times daily before meals is the only FDA-approved medication for gastroparesis and can address both gastric and intestinal dysmotility 1, 2, 3
- This is particularly important when gastroparesis symptoms (nausea, vomiting, early satiety) coexist with constipation 1
Second-Line Options for Persistent Constipation
If constipation persists despite stimulating laxatives: 1
- Rectal bisacodyl once daily 1
- Oral polyethylene glycol (osmotic laxative) 1
- Lactulose 1
- Magnesium hydroxide or magnesium citrate 1
For impaction: 1
Advanced Therapies for Refractory Cases
Peripherally acting μ-opioid receptor antagonists (particularly useful if opioids contribute to constipation): 1
- Methylnaltrexone 0.15 mg/kg every other day (no more than once daily) for patients not responding to standard laxative therapy 1
- This relieves opioid-induced constipation while maintaining pain control 1
- Naloxegol is an alternative peripherally-acting μ-opioid receptor antagonist 1
Alternative prokinetic agents if metoclopramide fails or is contraindicated: 1
- Erythromycin has been reported successful for constipation symptoms not responding to methylnaltrexone 1
- Prucalopride (5-HT4 receptor agonist) accelerates gastric emptying and colonic transit without cardiac risks 1
Newer secretagogue agents: 1
- Lubiprostone (prostaglandin analog that enhances intestinal fluid secretion) - can be combined with methylnaltrexone 1
- Linaclotide (guanylate cyclase-C receptor agonist) - effective for chronic constipation 1
Critical Pitfalls to Avoid
Do not use anticholinergic agents (scopolamine, antihistamines) for nausea in gastroparesis patients with constipation, as these will worsen bowel motility despite being listed as antiemetics for gastroparesis. 1 This creates a therapeutic conflict.
Avoid synthetic cannabinoids (dronabinol, nabilone) as they may slow gastric emptying and worsen constipation. 1
Monitor for metoclopramide side effects: The black box warning for tardive dyskinesia is important, though the actual risk may be lower than previously estimated. 1, 2 Extrapyramidal symptoms can occur, particularly in elderly patients. 1
Assess for mechanical obstruction before initiating aggressive bowel regimens - perform imaging if there is concern for impaction or obstruction. 1
Supportive Measures
Non-pharmacologic interventions: 1