Which medication's discontinuation is most likely to improve a patient's Vitamin B12 status?

Discontinuing metformin is most likely to improve a patient's Vitamin B12 status because this medication is known to be associated with Vitamin B12 deficiency. Metformin is often prescribed for the management of type 2 diabetes and has been linked to a decreased absorption of Vitamin B12 in the gut. This effect may occur through alterations in gut flora, changes in the gastrointestinal tract, or interference with the absorption mechanisms of Vitamin B12.

Patients on metformin may experience a gradual decrease in their Vitamin B12 levels, which, if left unmonitored, could lead to deficiency over time. Symptoms of Vitamin B12 deficiency can include fatigue, weakness, and neurological issues. Therefore, if a patient is experiencing deficiencies in Vitamin B12 and is on metformin, discontinuing or adjusting the dosage of this medication could potentially help restore their Vitamin B12 status.

Other medications listed do not commonly affect Vitamin B12 absorption in the same way. For instance, ACE inhibitors primarily affect blood pressure and do not have a direct impact on Vitamin B12 levels. Calcium carbonate, used as an antacid and a calcium supplement, does not interfere with Vitamin B12 absorption. Statins, used to manage cholesterol levels, also do not directly impact Vitamin B12 status.