What labs are monitored in patients on chronic Proton Pump Inhibitors (PPI)?

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From the Guidelines

Patients on chronic Proton Pump Inhibitor (PPI) therapy should have their vitamin B12, magnesium, and calcium levels monitored regularly, as well as their bone density, due to the potential for PPIs to interfere with the absorption of these nutrients and increase the risk of osteoporosis 1.

Recommended Labs

  • Complete Blood Count (CBC) to monitor for potential signs of vitamin B12 deficiency, such as anemia
  • Electrolyte panel, including magnesium and calcium levels, to assess for hypomagnesemia or hypocalcemia
  • Vitamin B12 level to evaluate for deficiency
  • Bone density test (e.g., DEXA scan) to assess for osteoporosis risk, especially in patients on long-term PPI therapy
  • Liver function tests (LFTs) to monitor for potential liver injury
  • Kidney function tests, including serum creatinine and estimated glomerular filtration rate (eGFR), to assess for chronic kidney disease These labs should be checked at least annually, or more frequently if the patient has underlying medical conditions or is taking other medications that may interact with PPIs 1.

Key Considerations

  • The risk of hypomagnesemia is higher in patients taking PPIs, especially at high doses or for extended periods 1
  • Vitamin B12 deficiency is also a concern, particularly in older adults or those taking PPIs for more than 1 year 1
  • Bone density should be monitored regularly, as PPI use has been linked to an increased risk of osteoporosis and fractures 1

From the FDA Drug Label

Monitor tacrolimus whole blood trough concentrations. Monitor INR and prothrombin time and adjust the dose of warfarin, if needed, to maintain target INR range Monitor digoxin concentrations. Monitor phenytoin serum concentrations. Monitor patients for increased sedation and reduce the dose of diazepam as needed.

The labs that are monitored in patients on chronic Proton Pump Inhibitors (PPI) include:

  • Tacrolimus levels: to assess for potential increased exposure, especially in transplant patients who are intermediate or poor metabolizers of CYP2C19 2, 3
  • INR and prothrombin time: to assess for potential increased risk of bleeding in patients receiving PPIs and warfarin concomitantly 3, 3
  • Digoxin concentrations: to assess for potential increased exposure 3, 3
  • Phenytoin serum concentrations: to assess for potential increased exposure 3
  • CgA levels: to assess for potential false positive results in diagnostic investigations for neuroendocrine tumors, consider temporarily stopping PPI treatment at least 14 days before assessing CgA levels 2, 3

From the Research

Labs Monitored in Patients on Chronic Proton Pump Inhibitors (PPI)

The following labs are monitored in patients on chronic PPI:

  • Full blood count [ 4, 5 ]
  • Iron [ 4, 6,7 ]
  • Ferritin [ 4, 5,7 ]
  • Vitamin D [ 4, 6,5,8 ]
  • Calcium [ 4, 6,5,8 ]
  • Sodium [ 4 ]
  • Potassium [ 4 ]
  • Phosphate [ 4 ]
  • Zinc [ 4, 6 ]
  • Folate [ 4 ]
  • Vitamin B12 [ 4, 6,7 ]
  • Magnesium [ 6, 8 ]
  • Cholesterol 5
  • Triglyceride 5
  • Low-density lipoprotein (LDL) 5
  • High-density lipoprotein (HDL) 5
  • Alkaline phosphatase (ALKP) 5
  • Aspartate aminotransferase (ASAT) 5
  • Alanine aminotransferase (ALAT) 5
  • Creatinine 5
  • Nitrogen blood urea 5

Rationale for Monitoring

These labs are monitored due to the potential adverse effects of chronic PPI use on micronutrient absorption, including:

  • Vitamin B12 deficiency 6, 7
  • Hypocalcemia 6, 8
  • Hypomagnesemia 6, 8
  • Iron deficiency 6
  • Zinc deficiency 4, 6

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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