Proton Pump Inhibitor Drug Interactions Every Pharmacy Tech Should Know
Learn the most critical PPI drug interactions tested on the PTCB exam, including clopidogrel, methotrexate, and key counseling points.
Why PPI Drug Interactions Matter on the PTCB Exam
Proton pump inhibitors (PPIs) like omeprazole, lansoprazole, and pantoprazole are among the most commonly dispensed medications. Understanding their drug interactions is essential for patient safety and a frequent topic on the PTCB certification exam.
High-Priority PPI Interactions
Clopidogrel (Plavix)
Omeprazole and esomeprazole inhibit CYP2C19, reducing the antiplatelet effect of clopidogrel. Pantoprazole is generally considered the safer alternative when a PPI is needed alongside clopidogrel.
Methotrexate
PPIs can decrease renal clearance of methotrexate, potentially leading to toxicity. Watch for this combination especially in patients on high-dose methotrexate therapy.
Iron and Calcium Supplements
PPIs raise gastric pH, which reduces absorption of iron salts and calcium carbonate. Patients may need calcium citrate instead, as its absorption is less pH-dependent.
Additional Interactions to Review
- Warfarin: PPIs (especially omeprazole) may increase INR by inhibiting CYP2C19 metabolism
- Tacrolimus: PPI co-administration can raise tacrolimus levels, requiring monitoring
- HIV protease inhibitors: Atazanavir and nelfinavir require acidic pH for absorption
- Benzodiazepines: Omeprazole may slow diazepam metabolism
Long-Term PPI Risks
Extended PPI use is associated with magnesium depletion, vitamin B12 deficiency, increased fracture risk, and Clostridium difficile infection. Pharmacy technicians should flag prolonged use for pharmacist review.
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