Prilosec (Omeprazole) is NOT a Treatment for Colitis
Prilosec (omeprazole) has no established role in the treatment of colitis and is not recommended by any major gastroenterology guidelines. In fact, proton pump inhibitors like omeprazole may actually cause microscopic colitis in some patients.
Evidence-Based Treatment for Colitis
The appropriate treatment for colitis depends entirely on the specific type and severity:
For Inflammatory Bowel Disease (Ulcerative Colitis/Crohn's Colitis)
First-line therapy for mild to moderate colitis is high-dose mesalazine (2-4 g daily), NOT omeprazole 1, 2:
- Mild disease: Start with mesalazine 4 g daily as initial therapy 1, 2
- Moderate to severe disease: Use oral prednisolone 40 mg daily, tapered gradually over 8 weeks 1, 2
- Severe disease requiring hospitalization: Intravenous methylprednisolone 60 mg daily or hydrocortisone 400 mg daily 1, 3
- Maintenance therapy: Azathioprine 1.5-2.5 mg/kg/day or mercaptopurine 0.75-1.5 mg/kg/day to prevent relapse 1, 2
For Microscopic Colitis
Budesonide 9 mg daily is the first-line treatment, with mesalamine as an alternative 1:
- Budesonide is more than twice as effective as mesalamine for inducing clinical remission 1
- Bismuth salicylate may be considered if budesonide is not feasible 1
Why Omeprazole Should NOT Be Used
PPIs May Actually Cause Microscopic Colitis
Proton pump inhibitors, including omeprazole and lansoprazole, are associated with causing microscopic colitis, not treating it 4, 5, 6:
- Multiple case series document PPI-induced microscopic colitis that resolved upon discontinuation 4, 6
- A systematic review found a possible association between PPIs and development of microscopic colitis 5
- Lansoprazole specifically has been linked to both collagenous and lymphocytic colitis subtypes 4, 6
Lack of Evidence for Therapeutic Benefit
The only "evidence" for omeprazole in colitis consists of:
These anecdotal reports are vastly outweighed by established guideline-based treatments with proven efficacy in large randomized trials 1, 2.
Clinical Pitfall to Avoid
If a patient with colitis is taking a PPI and develops worsening diarrhea, consider PPI-induced microscopic colitis and discontinue the PPI 4, 6. Symptoms typically resolve within 4-10 days of stopping the medication, with histological normalization on follow-up biopsies 4, 6.
The Correct Approach
Use evidence-based anti-inflammatory therapy (mesalazine, corticosteroids, immunomodulators, or biologics) based on colitis type and severity, not acid suppression therapy 1, 2. PPIs should only be prescribed if the patient has a separate indication for acid suppression (such as GERD or peptic ulcer disease), not for colitis treatment itself.