Drug contra-Indicated in bilateral renal aery stenosis
**Core Concept**
Bilateral renal artery stenosis is a condition characterized by the narrowing of both renal arteries, which supply blood to the kidneys. This can lead to decreased renal function and increased risk of renal failure. In this context, certain medications can exacerbate the condition or be contraindicated due to their effects on the renin-angiotensin-aldosterone system (RAAS).
**Why the Correct Answer is Right**
The correct answer is a drug that can cause vasoconstriction, activate the RAAS, or increase blood pressure, which can worsen renal function in patients with bilateral renal artery stenosis. Nonsteroidal anti-inflammatory drugs (NSAIDs) like indomethacin work by inhibiting prostaglandin synthesis, leading to vasoconstriction and decreased renal blood flow. This can be particularly problematic in patients with bilateral renal artery stenosis, where the kidneys are already receiving decreased blood flow.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the question. While certain medications may be contraindicated in patients with renal artery stenosis, this option does not address the specific issue of bilateral renal artery stenosis.
**Option B:** This option is not directly related to the contraindication in bilateral renal artery stenosis. While certain antihypertensive medications may be contraindicated in patients with renal artery stenosis, this option does not address the specific issue of bilateral renal artery stenosis.
**Option C:** This option is not relevant to the question. While certain medications may be contraindicated in patients with renal disease, this option does not address the specific issue of bilateral renal artery stenosis.
**Option D:** This option is not directly related to the contraindication in bilateral renal artery stenosis. While certain medications may be contraindicated in patients with renal disease, this option does not address the specific issue of bilateral renal artery stenosis.
**Clinical Pearl / High-Yield Fact**
In patients with bilateral renal artery stenosis, NSAIDs like indomethacin can worsen renal function by inhibiting prostaglandin synthesis and causing vasoconstriction. This is a classic exam trap that can be remembered by the phrase "NSAIDs in renal stenosis = renal disaster".
**Correct Answer: A. Indomethacin**