Question

Which effect is associated with amphotericin B?

• A. Hyponatremia
• B. Hypokalemia
• C. Hypermagnesemia
• D. Hypercalcemia

Hint:

Monitor serum electrolytes, especially potassium and magnesium, during amphotericin B therapy to prevent serious complications.

Answer 1

The Correct Option is B

Amphotericin B is a polyene antifungal agent used primarily to treat systemic fungal infections. One of its notable adverse effects is renal toxicity, which leads to electrolyte disturbances. - Amphotericin B binds to ergosterol in fungal cell membranes, creating pores that cause leakage of intracellular components. Unfortunately, it can also affect mammalian kidney cells.
- This nephrotoxicity results in increased renal tubular permeability leading to loss of potassium and magnesium in the urine.
- Consequently, patients often develop hypokalemia (low serum potassium levels), which can cause muscle weakness, cardiac arrhythmias, and other clinical manifestations.
- Other electrolyte abnormalities may occur but hypokalemia is the hallmark electrolyte disturbance linked with amphotericin B therapy.

Answer 2

Amphotericin B is known for a distinctive type of kidney toxicity that disturbs electrolyte balance in a specific direction. Let's check what happens to each electrolyte listed in the options.

1. Hyponatremia: Amphotericin B damages the distal renal tubule and increases its permeability, which mainly causes loss of potassium and magnesium in the urine rather than sodium. Sodium handling is not the primary electrolyte problem with this drug, so this option is incorrect.
2. Hypokalemia: The pores amphotericin B punches into the distal tubular cell membrane let potassium leak out into the urine faster than the kidney can reclaim it. This renal potassium wasting is the best documented electrolyte side effect of the drug and often needs potassium supplementation during therapy, so this option is correct.
3. Hypermagnesemia: The same tubular damage that wastes potassium also wastes magnesium, but it lowers magnesium levels rather than raising them, so this describes the wrong direction of change and is incorrect.
4. Hypercalcemia: Amphotericin B is not known to raise serum calcium, and calcium handling is not the electrolyte axis this drug disturbs, so this option is incorrect.

The electrolyte disturbance that fits amphotericin B's mechanism of distal tubular damage and renal wasting is low serum potassium.

Therefore, the correct answer is Hypokalemia.