American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What types of metabolic derangement is associated with Sulfamylon (mafenide acetate)?

1. Metabolic alkalosis

2. Respiratory acidosis

3. Metabolic acidosis

4. Hypercapnia

The correct answer is: Metabolic acidosis

Sulfamylon, or mafenide acetate, is a topical antimicrobial used primarily in the treatment of third-degree burns and to prevent infection in burn wounds. One of the metabolic derangements associated with its use is metabolic acidosis. This occurs due to the drug's ability to inhibit carbonic anhydrase, an enzyme that plays a crucial role in acid-base balance by facilitating the conversion of carbon dioxide and water into bicarbonate and protons. When carbonic anhydrase is inhibited, there is a decrease in bicarbonate production, leading to an accumulation of hydrogen ions and a resultant drop in pH, which manifests as metabolic acidosis. In patients treated with Sulfamylon, particularly those with extensive burns, the body also faces significant fluid losses and potential tissue injury, contributing to further metabolic disturbances. The impaired ability to manage acid-base balance can exacerbate this condition, making close monitoring and management critical in these patients. Therefore, metabolic acidosis is the key metabolic derangement associated with the use of Sulfamylon.