Maximum hypoglycemia is caused by which oral hypoglycomic –
**Core Concept**
The question tests the knowledge of the mechanism of hypoglycemia associated with oral antidiabetic drugs. Oral hypoglycemic agents can cause hypoglycemia by enhancing insulin secretion or by inhibiting hepatic glucose production. The correct answer is an oral hypoglycemic agent that has a high risk of causing hypoglycemia due to its mechanism of action.
**Why the Correct Answer is Right**
The correct answer is **Glibenclamide** (also known as Glyburide). Glibenclamide is a second-generation sulfonylurea that works by stimulating the release of insulin from the pancreatic beta cells by binding to and activating the ATP-sensitive potassium channels. This leads to a rapid increase in insulin secretion, which can cause hypoglycemia. Glibenclamide has a long duration of action and can cause prolonged hypoglycemia, making it one of the oral hypoglycemic agents with the highest risk of hypoglycemia.
**Why Each Wrong Option is Incorrect**
* **Option A:** Metformin is a biguanide that works by decreasing hepatic glucose production and increasing insulin sensitivity. It does not cause hypoglycemia at therapeutic doses.
* **Option B:** Pioglitazone is a thiazolidinedione that works by increasing insulin sensitivity. It does not cause hypoglycemia at therapeutic doses.
* **Option C:** Sitagliptin is a DPP-4 inhibitor that works by increasing the levels of incretin hormones, which in turn increase insulin secretion. While it can cause hypoglycemia, it is not as likely to cause severe hypoglycemia as glibenclamide.
**Clinical Pearl / High-Yield Fact**
Be aware that sulfonylureas like glibenclamide can cause prolonged hypoglycemia due to their long duration of action, and patients taking these medications should be advised to carry glucose tablets or candy with them at all times.
**Correct Answer:** D. Glibenclamide.