How to manage a patient with Vitamin B12 deficiency, back pain on Celebrex (celecoxib), and impaired renal function, with a history of alcohol use and omeprazole (proton pump inhibitor) therapy?

Management of Vitamin B12 Deficiency, Back Pain on Celebrex, and Declining Renal Function

Immediate Priority: Discontinue Celebrex and Initiate B12 Replacement

Stop celecoxib immediately given the declining renal function (eGFR 72→64) and initiate intramuscular hydroxocobalamin 1000 mcg for B12 deficiency (121 pmol/L). 1, 2

---

Vitamin B12 Deficiency Management

Treatment Protocol

Initiate hydroxocobalamin 1000 mcg intramuscularly three times weekly for 2 weeks, then transition to monthly maintenance dosing for life. 1 This patient has clear B12 deficiency (121 pmol/L, normal 170-800) with two contributing factors: chronic omeprazole use and alcohol consumption.

• The FDA label explicitly warns that omeprazole therapy longer than 3 years may lead to cyanocobalamin malabsorption due to hypo- or achlorhydria 2
• Research demonstrates omeprazole acutely decreases B12 absorption in a dose-dependent manner, reducing absorption from 3.2% to 0.9% after just 2 weeks 3
• Patients on long-term PPI therapy (>4 years) should be monitored for B12 status 4

Critical Consideration: Avoid Cyanocobalamin in Renal Dysfunction

Use hydroxocobalamin or methylcobalamin instead of cyanocobalamin given the declining renal function. 1 Cyanocobalamin requires renal clearance of the cyanide moiety and is associated with increased cardiovascular events (HR 2.0) in patients with diabetic nephropathy and impaired renal function. 1

Monitoring Schedule

• Recheck B12 levels at 3 months, 6 months, and 12 months after initiating treatment 1
• Measure complete blood count to assess for resolution of any megaloblastic anemia 1
• Check homocysteine levels with target <10 μmol/L for optimal outcomes 1
• Once levels stabilize for two consecutive checks, transition to annual monitoring 1

Address Contributing Factors

Consider reducing or discontinuing omeprazole if clinically feasible, as it is the primary driver of B12 malabsorption. 2, 5, 4 The patient is also on famotidine, suggesting possible overuse of acid suppression. If heartburn persists, consider:

• Lifestyle modifications (elevate head of bed, avoid triggers) 6
• Use the lowest effective dose and shortest duration of PPI therapy 2
• Evaluate for H. pylori if not previously tested 2

Counsel on alcohol reduction, as alcohol use contributes to both B12 deficiency and thiamine deficiency risk. 6 Consider thiamine supplementation given the alcohol history and risk of Wernicke's encephalopathy. 6

---

Back Pain Management: Discontinue Celebrex

Rationale for Discontinuation

Celecoxib (Celebrex) is contraindicated in this patient with declining renal function (eGFR 72→64). NSAIDs, including selective COX-2 inhibitors like celecoxib, cause dose-dependent renal toxicity through inhibition of prostaglandin-mediated renal blood flow. The 11% decline in eGFR over this time period is concerning and likely NSAID-related.

Alternative Pain Management Strategies

First-line: Acetaminophen up to 3000 mg daily in divided doses (avoid higher doses given alcohol use and potential hepatotoxicity risk). This provides adequate analgesia for chronic back pain without renal toxicity.

Second-line options if acetaminophen insufficient:

• Topical NSAIDs (diclofenac gel) for localized pain—minimal systemic absorption and renal impact
• Physical therapy and core strengthening exercises
• Consider referral to pain management for non-pharmacologic interventions (e.g., epidural steroid injections if radicular symptoms present)

Avoid:

• All oral NSAIDs (ibuprofen, naproxen, meloxicam) given renal dysfunction
• Opioids as first-line therapy given addiction risk and lack of evidence for chronic non-cancer pain

---

Renal Function Monitoring

Assess for Reversibility

Recheck renal function (creatinine, eGFR) 2-4 weeks after discontinuing celecoxib to assess for improvement. 6 If eGFR improves, this confirms NSAID-related nephrotoxicity. If eGFR continues to decline, investigate other causes:

• Urinalysis with microscopy to evaluate for proteinuria, hematuria, or casts
• Renal ultrasound to assess for structural abnormalities
• Consider nephrology referral if eGFR <60 or continues declining

Medication Adjustments for Renal Function

• Magnesium supplementation: Use caution with magnesium supplements if eGFR continues to decline, as magnesium is renally cleared 2
• Monitor for PPI-related hypomagnesemia: Check magnesium levels periodically, as PPIs can cause hypomagnesemia after ≥3 months of use 2
• Avoid nephrotoxic medications: Review all medications for renal dosing adjustments

---

Omeprazole Risk-Benefit Reassessment

Long-term PPI Complications

This patient faces multiple PPI-related risks beyond B12 deficiency:

• Bone fracture risk: Long-term PPI use (≥1 year) increases risk of osteoporosis-related fractures of hip, wrist, or spine 2
• Hypomagnesemia: Risk after ≥3 months of therapy, can cause tetany, arrhythmias, seizures 2
• Fundic gland polyps: Risk increases with use beyond 1 year 2
• C. difficile infection: Increased risk of severe diarrhea 2

Deprescribing Strategy

Attempt PPI deprescribing by:

1. Switching to on-demand dosing (take only when symptomatic)
2. Step-down to H2-blocker monotherapy (famotidine) if symptoms controlled
3. Trial off all acid suppression with lifestyle modifications if symptoms minimal

If PPI continuation necessary: Use lowest effective dose, monitor B12 annually, ensure adequate calcium and vitamin D supplementation for bone health, and monitor magnesium levels periodically. 2

---

Additional Nutritional Considerations

Comprehensive Vitamin Assessment

Given alcohol use, PPI therapy, and declining renal function, consider screening for:

• Thiamine (B1): Alcohol use increases risk of deficiency; supplement if deficient to prevent Wernicke's encephalopathy 6
• Folate: Check levels, but never supplement folic acid before ensuring adequate B12 treatment, as it can mask B12 deficiency while allowing irreversible neurological damage 1
• Vitamin D: Check 25-OH vitamin D levels; supplement if <30 ng/mL given bone fracture risk from PPI use 6
• Zinc and magnesium: Monitor given PPI use and potential malabsorption 6

Nutritional Counseling

• Ensure adequate protein intake (1.2-1.5 g/kg/day) and caloric intake (35-40 kcal/kg/day) 6
• Encourage B12-rich foods (meat, fish, dairy), though supplementation remains necessary given malabsorption
• Counsel on alcohol reduction with specific targets (e.g., ≤2 drinks per day for men)

---

Common Pitfalls to Avoid

1. Do not use cyanocobalamin for B12 replacement in this patient with renal dysfunction—use hydroxocobalamin or methylcobalamin 1
2. Do not continue celecoxib despite symptomatic benefit—renal preservation takes priority over pain control
3. Do not supplement folic acid before confirming adequate B12 treatment and levels 1
4. Do not assume B12 levels will normalize after stopping omeprazole alone—active replacement is required 5, 4
5. Do not stop B12 injections after symptoms improve or levels normalize—this patient requires lifelong therapy given ongoing PPI use and malabsorption 1