**Core Concept:** Chlorpropamide is an old-generation sulfonylurea insulin sensitizer used in the treatment of type 2 diabetes mellitus. It works by enhancing glucose uptake by muscle and adipose tissues and decreasing hepatic glucose production. However, it can cause various adverse effects.

**Why the Correct Answer is Right:**

The correct answer is **D**. Chlorpropamide can lead to the following adverse effects:

1. Gastrointestinal disturbances: This includes nausea, vomiting, diarrhoea, and abdominal pain. It is a common side effect due to the drug's mechanism of action, which involves increasing insulin sensitivity.
2. Hypoglycaemia: Chlorpropamide can cause hypoglycaemia due to its insulin-sensitizing properties. This is because, although it helps reduce blood glucose levels, it can also lead to increased insulin levels and hypoglycaemia if not used appropriately.
3. Hypersensitivity reactions: All sulfonylureas, including chlorpropamide, have the potential to cause hypersensitivity reactions such as rash, urticaria, and angioedema.
4. Hepatotoxicity: Although rare, chlorpropamide can cause liver damage, leading to elevated liver enzymes, hepatitis, and in severe cases, liver failure.

**Why Each Wrong Option is Incorrect:**

Option A is incorrect because chlorpropamide can cause hypoglycaemia, which is a known adverse effect of the drug.

Option B is incorrect as it is the mechanism of action of chlorpropamide, not an adverse effect.

Option C is incorrect because chlorpropamide can cause hypersensitivity reactions, such as rash and urticaria, but it does not specifically affect the cardiovascular system.

**Clinical Pearl:**

Clinicians should be aware of the potential adverse effects of chlorpropamide, especially hypersensitivity reactions and hepatotoxicity. The drug should be used judiciously and monitored closely for signs of hypoglycaemia and liver dysfunction. It is crucial to consider alternative antidiabetic drugs in patients who experience severe adverse reactions or develop hepatotoxicity.