Which of the following antidiabetic drugs can cause vitamin B12 deficiency?
**Core Concept**
The question tests the student's knowledge of the side effects of antidiabetic medications, specifically those that can lead to vitamin B12 deficiency. This deficiency can have significant clinical implications, including neurological and hematological effects. **Metformin** is a commonly used antidiabetic drug that can cause vitamin B12 deficiency.
**Why the Correct Answer is Right**
**Metformin** can cause vitamin B12 deficiency by interfering with its absorption in the gut. This is thought to occur through a decrease in the absorption of vitamin B12-intrinsic factor complexes. The exact mechanism is not fully understood, but it is known that long-term use of **metformin** can lead to a decrease in vitamin B12 levels.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not associated with vitamin B12 deficiency.
**Option C:** This option is incorrect because it does not typically cause vitamin B12 deficiency.
**Clinical Pearl / High-Yield Fact**
It is essential to monitor vitamin B12 levels in patients taking **metformin** for an extended period, as a deficiency can cause significant clinical symptoms. A classic symptom of vitamin B12 deficiency is megaloblastic anemia.
**Correct Answer:** D. Metformin.