Can Seroquel (quetiapine) cause constipation?

Does Quetiapine Cause Constipation?

Yes, quetiapine (Seroquel) commonly causes constipation due to its anticholinergic effects, with constipation reported in 8-10% of patients taking the medication, which is significantly higher than placebo rates of 3-4%. 1

Mechanism of Action

Quetiapine causes constipation primarily through its metabolite norquetiapine, which has moderate to strong affinity for muscarinic receptor subtypes, resulting in anticholinergic effects that reduce intestinal motility 1. This anticholinergic activity:

• Decreases intestinal peristalsis
• Reduces secretion of intestinal fluids
• Increases intestinal transit time

Risk Factors and Severity

The risk of constipation with quetiapine may be increased by:

• Higher doses (dose-dependent effect) 1
• Concurrent use of other medications with anticholinergic properties 2
• Advanced age
• Pre-existing gastrointestinal disorders
• Dehydration or low fluid intake

Clinical Significance and Complications

Constipation from quetiapine is not merely a minor side effect but can lead to serious complications:

• Intestinal obstruction (including fatal cases) has been reported in patients taking quetiapine 1
• Severe cases can progress to ischemic colitis 2, 3
• In rare cases, gastrointestinal necrosis has been reported with quetiapine, similar to what has been observed with clozapine 4

Management Recommendations

For patients prescribed quetiapine who develop constipation:

1. Preventive measures:

   • Ensure adequate hydration
   • Increase physical activity when appropriate
   • Consider prophylactic laxative therapy when starting quetiapine 5

2. Treatment options:

   • First-line: Stimulant laxatives to increase bowel motility 5
   • Add osmotic laxatives (polyethylene glycol, lactulose, magnesium salts) if constipation persists 5
   • Avoid bulk-forming laxatives in patients with inadequate fluid intake 5

3. For refractory cases:

   • Consider peripherally acting μ-opioid receptor antagonists like methylnaltrexone (0.15 mg/kg every other day) 5
   • Prokinetic agents like metoclopramide may be considered if gastroparesis is suspected 5

Monitoring and Precautions

• Quetiapine should be used with caution in patients with a history of constipation, urinary retention, or clinically significant prostatic hypertrophy 1
• Regular monitoring of bowel movements is essential in patients taking quetiapine 2
• Prompt recognition and management of constipation is critical to prevent serious complications 1, 2
• Consider dose reduction or medication switch if constipation is severe or persistent

Clinical Pearls

• The constipating effect of quetiapine can be observed in both immediate-release and extended-release formulations 6
• The combination of quetiapine with other anticholinergic medications significantly increases the risk of severe constipation and potential complications 2, 3
• Constipation is one of the most common adverse effects leading to discontinuation of quetiapine in clinical trials 1
• Patients should be educated about this side effect and encouraged to report constipation promptly

In summary, constipation is a well-documented side effect of quetiapine that requires proactive monitoring and management to prevent potentially serious complications.