What antibiotics can cause constipation?

Antibiotics That Can Cause Constipation

Opioids are the most common medications associated with constipation, but several antibiotics can also cause constipation, particularly clindamycin, fluoroquinolones, and some cephalosporins. 1

Common Constipation-Causing Antibiotics

Primary Culprits:

• Clindamycin: Despite being more notorious for causing diarrhea and C. difficile infection, it can also cause constipation in some patients 2
• Fluoroquinolones (e.g., ciprofloxacin): Can affect gut motility and contribute to constipation 1
• Cephalosporins (especially third/fourth generation): May cause constipation as a side effect 3

Other Antibiotics with Constipation Risk:

• Vancomycin (particularly oral form): Can alter gut flora in ways that may lead to constipation 4
• Metronidazole: When used long-term, may contribute to motility disorders 1
• Rifaximin: Used for SIBO but can sometimes cause constipation 1

Mechanism of Antibiotic-Induced Constipation

Antibiotics can cause constipation through several mechanisms:

1. Alteration of gut microbiota: Disruption of normal intestinal flora can affect gut motility 3
2. Direct effects on intestinal smooth muscle: Some antibiotics have antimuscarinic properties that slow intestinal transit 5
3. Changes in gut secretion: Affecting fluid balance in the intestine 5
4. Neuromuscular effects: Some antibiotics may affect the enteric nervous system 1

Risk Factors for Antibiotic-Induced Constipation

• Advanced age (≥65 years)
• Concurrent use of other constipating medications
• Dehydration
• Immobility
• Pre-existing gastrointestinal disorders
• Longer duration of antibiotic therapy 1

Management of Antibiotic-Induced Constipation

Preventive Measures:

• Maintain adequate hydration
• Increase dietary fiber if tolerated
• Regular physical activity when possible
• Consider prophylactic stool softeners for high-risk patients 1

Treatment Approach:

1. First-line: Stimulant laxatives (e.g., bisacodyl 10-15 mg, 2-3 times daily) 1
2. Add-on options:
   • Polyethylene glycol
   • Lactulose
   • Magnesium hydroxide
   • Magnesium citrate 1
3. For severe cases: Consider peripherally acting μ-opioid receptor antagonists if opioids are also being used 1

Special Considerations

• Patients with chronic intestinal motility disorders: May require prokinetics or specialized management 1
• Patients on multiple antibiotics: Higher risk of constipation, especially with combinations including clindamycin or fluoroquinolones 3
• Long-term antibiotic therapy: May benefit from rotating antibiotics to reduce constipation risk 1

Clinical Pitfalls to Avoid

• Don't ignore constipation: It can lead to impaction, obstruction, and reduced quality of life 1
• Don't automatically attribute all GI symptoms to C. difficile: While antibiotics are known for causing C. difficile-associated diarrhea, constipation is also a common side effect 6
• Don't overlook drug interactions: Some antibiotics may interact with other medications to increase constipation risk 1
• Don't continue unnecessary antibiotics: Antibiotic stewardship is important to minimize all side effects, including constipation 3

When constipation occurs during antibiotic therapy, consider whether the antibiotic is essential or if an alternative with less constipating potential could be substituted, while ensuring appropriate coverage for the infection being treated.