Does Bupropion Cause Constipation?
Yes, constipation is a well-established and common side effect of bupropion across all formulations. This adverse effect is consistently documented in FDA labeling, clinical guidelines, and research literature.
Evidence from FDA Labeling and Guidelines
Constipation is explicitly listed as one of the most common side effects of bupropion in the FDA-approved drug label 1. The American Diabetes Association guidelines identify constipation as a common side effect when bupropion is used in combination with naltrexone for weight management 2. The American College of Cardiology and other medical societies acknowledge that bupropion commonly causes constipation along with dry mouth, insomnia, headache, dizziness, nausea, and tremor 3.
Frequency and Clinical Significance
- Constipation occurs frequently enough to be listed among the primary common adverse effects across multiple authoritative sources 2, 3, 1
- In clinical trials of naltrexone/bupropion combinations for obesity, approximately half of patients experienced gastrointestinal disorders including constipation 4
- The constipation can range from mild to severe, with at least one documented case requiring surgical intervention 5
Clinical Case Evidence
A published case report documented severe constipation leading to thrombotic hemorrhoids requiring hemorrhoidectomy in a 38-year-old man taking extended-release bupropion 150 mg daily 5. The constipation developed within three weeks of starting treatment and resolved only after discontinuation of bupropion, establishing a clear temporal relationship 5.
Mechanism and Formulation Considerations
- All bupropion formulations (immediate-release, sustained-release, and extended-release) are associated with constipation 6, 7
- The mechanism likely relates to bupropion's effects on norepinephrine and dopamine neurotransmission, which can affect gastrointestinal motility 6
- Constipation is reported as a common adverse effect in both depression treatment and smoking cessation indications 7
Clinical Management Recommendations
When prescribing bupropion, clinicians should:
- Proactively counsel patients about the risk of constipation before initiating therapy 3, 1
- Recommend preventive measures including increased fluid intake, dietary fiber, and regular exercise 5
- Consider prophylactic stool softeners (such as docusate sodium) for patients at higher risk 5
- Monitor for constipation at follow-up visits, particularly in the first few weeks of treatment 5
- Be prepared to discontinue bupropion if severe constipation develops that does not respond to conservative management 5
Important Caveats
While constipation is common, it should not be confused with contraindications related to eating disorders 3. Bupropion is contraindicated in patients with anorexia or bulimia nervosa due to increased seizure risk, not because of gastrointestinal effects 3. Simple nausea or vomiting are side effects, not contraindications 3.