A 68-year-old woman presents to the clinic with symptoms and signs of CHF. Which of the following is a contraindication to use furosemide?
## **Core Concept**
Furosemide is a loop diuretic commonly used in the management of congestive heart failure (CHF) to reduce fluid overload. It works by inhibiting the sodium-potassium-chloride cotransporter in the thick ascending limb of the loop of Henle, leading to increased urine production. However, its use can be contraindicated in certain conditions due to its mechanism of action and side effects.
## **Why the Correct Answer is Right**
The correct answer is related to a condition where the use of furosemide would be harmful. Furosemide is contraindicated in patients with **severe hypokalemia**, **hypovolemia**, or **anuria** that is unresponsive to furosemide. Most notably, a critical contraindication is **sulfonamide allergy** because furosemide is a sulfonamide derivative, and administering it to someone with a known allergy to sulfonamides can provoke an allergic reaction.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, but typically, conditions like hypokalemia or hypovolemia are not absolute contraindications but rather require cautious use and correction before administering furosemide.
- **Option B:** Similarly, this option cannot be evaluated without content but might represent conditions where caution is needed rather than strict contraindication.
- **Option C:** This could potentially represent a condition where furosemide is used cautiously or with dose adjustments rather than being a strict contraindication.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that patients with **sulfonamide allergies** should avoid furosemide due to the risk of cross-reactivity. Additionally, furosemide should be used cautiously in patients with **hepatic cirrhosis** and **ascites** because it can precipitate hepatic encephalopathy.
## **Correct Answer: D. Sulfonamide allergy**