Minor
Cyanocobalamin × Omeprazole
Vitamins. Haemopoietic stimulants×Proton pump inhibitors
Mechanism
Proton pump inhibitors suppress gastric acidity and reduce B12 release from food (which requires HCl and pepsin). For short courses (up to 8 weeks), clinically insignificant. With long-term therapy (over 2 years), B12 deficiency risk is reported.
Symptoms
On long-term therapy: fatigue, pallor, paraesthesias in hands and feet, gait instability, memory decline.
Management
For short omeprazole courses, no adjustment needed. On long-term therapy (over 2 years), check B12 yearly. If it falls below 200 pg/mL, give cyanocobalamin 500–1000 mcg/day orally — passive diffusion absorption at high doses works regardless of acidity.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.