A 65-year-old male with CHF exacerbation is given IV furosemide. Which of the following adverse events are not associated with this medication
**Core Concept**
Furosemide is a loop diuretic that acts by inhibiting the Na-K-2Cl cotransporter in the ascending limb of the loop of Henle, leading to increased renal excretion of sodium, chloride, and water. This results in increased urine production and a decrease in blood volume, which is beneficial in treating congestive heart failure (CHF) exacerbation by reducing fluid overload.
**Why the Correct Answer is Right**
Furosemide's mechanism of action involves the inhibition of the Na-K-2Cl cotransporter, which is responsible for the reabsorption of sodium, potassium, and chloride ions in the ascending limb of the loop of Henle. The increased excretion of these ions leads to a decrease in blood volume and an increase in urine production, which helps to alleviate fluid overload in CHF patients. The correct answer is associated with furosemide's mechanism of action, which does not directly involve the inhibition of the carbonic anhydrase enzyme.
**Why Each Wrong Option is Incorrect**
**Option A:** Ototoxicity is a known adverse effect of furosemide, particularly at high doses. This is due to the drug's ability to inhibit the production of prostaglandins, which are essential for the maintenance of the inner ear's endolymphatic system.
**Option B:** Hypokalemia is also a well-documented adverse effect of furosemide, as the increased excretion of potassium ions can lead to a decrease in serum potassium levels.
**Option C:** Hyperglycemia is not a direct adverse effect of furosemide. However, patients with diabetes mellitus may experience hyperglycemia due to the increased glucose production in the liver, which is stimulated by the increased glucagon levels caused by furosemide-induced dehydration.
**Option D:** Carbonic anhydrase inhibition is not a mechanism of action associated with furosemide. Carbonic anhydrase inhibitors, such as acetazolamide, act by inhibiting the enzyme carbonic anhydrase, which is responsible for the reabsorption of bicarbonate ions in the proximal convoluted tubule.
**Clinical Pearl / High-Yield Fact**
Furosemide can cause a decrease in serum magnesium levels due to increased excretion, which can lead to hypomagnesemia. This is an important consideration in patients with CHF, as hypomagnesemia can exacerbate arrhythmias and other cardiac complications.
**Correct Answer:** D. Carbonic anhydrase inhibition is not a mechanism of action associated with furosemide.