Which chronic medication can cause B12 deficiency?

Which chronic medication can cause B12 deficiency?

• A. Metformin
• B. Levothyroxine
• C. Statins
• D. ACE inhibitors

Answer: (A)

Metformin is the medication known to cause B12 deficiency with long-term use. The mechanism involves interference with calcium-dependent absorption of the B12–intrinsic factor complex in the terminal ileum, so ongoing metformin therapy can reduce B12 uptake over months to years. This deficiency can present subtly but may cause fatigue from macrocytic anemia and neuropathy that can resemble diabetic nerve damage, making it important to check B12 levels in patients on chronic metformin who develop neuropathic symptoms or anemia. If B12 deficiency is suspected or confirmed, supplementation is the treatment, using cyanocobalamin or hydroxocobalamin, with the approach (oral high-dose versus parenteral) guided by the severity of absorption. Other drugs listed—levothyroxine, statins, and ACE inhibitors—do not have a typical association with inducing B12 deficiency.

Metformin is the medication known to cause B12 deficiency with long-term use. The mechanism involves interference with calcium-dependent absorption of the B12–intrinsic factor complex in the terminal ileum, so ongoing metformin therapy can reduce B12 uptake over months to years. This deficiency can present subtly but may cause fatigue from macrocytic anemia and neuropathy that can resemble diabetic nerve damage, making it important to check B12 levels in patients on chronic metformin who develop neuropathic symptoms or anemia. If B12 deficiency is suspected or confirmed, supplementation is the treatment, using cyanocobalamin or hydroxocobalamin, with the approach (oral high-dose versus parenteral) guided by the severity of absorption. Other drugs listed—levothyroxine, statins, and ACE inhibitors—do not have a typical association with inducing B12 deficiency.