## **Core Concept**
The question tests understanding of the side effects of antihypertensive drugs, specifically the risk of orthostatic hypotension. Orthostatic hypotension is a sudden drop in blood pressure that occurs upon standing, which can lead to dizziness or fainting. Different classes of antihypertensive drugs have varying effects on the body's ability to regulate blood pressure in response to changes in posture.

## **Why the Correct Answer is Right**
The correct answer, , is associated with the class of drugs known as alpha-1 blockers or direct vasodilators, but most prominently with drugs that significantly affect venous capacitance vessels or have a potent effect on arteriolar dilation without compensatory tachycardia. However, among the typical antihypertensive classes, **non-selective beta-blockers without intrinsic sympathomimetic activity (ISA)** and certain **direct vasodilators** can cause significant issues, but **alpha blockers** and **hydralazine** are notable. Yet, **centrally acting agents** like methyldopa can cause significant postural hypotension due to their effect on the autonomic nervous system. But among the given options and common antihypertensive drugs, **prazosin (an alpha-1 blocker)** is well-known for causing significant orthostatic hypotension, especially with the first dose.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Typically less likely to cause significant orthostatic hypotension compared to alpha blockers or certain direct vasodilators.
- **Option B:** May cause hypotension but often less severe orthostatic effects compared to alpha-1 blockers.
- **Option C:** Generally associated with less risk of orthostatic hypotension compared to alpha blockers.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **alpha-1 blockers**, such as **prazosin**, are notorious for causing significant **first-dose hypotension** and orthostatic hypotension. This effect is so pronounced that the first dose is often administered at bedtime to minimize the risk of dizziness or falls.

## **Correct Answer:** .