Acetylcysteine (Mucomyst) is a mucolytic that can also be used in the treatment of overdosage of which drug?
A.
Ibuprofen
B.
Diphenhydramine
C.
Acetaminophen
D.
Amoxicillin
The Correct Answer and Explanation is:
The correct answer is C. Acetaminophen.
Acetylcysteine (Mucomyst) is primarily known as a mucolytic agent, used to break down and thin mucus in conditions such as chronic obstructive pulmonary disease (COPD) and cystic fibrosis. However, it has another critical application as an antidote in the treatment of acetaminophen (Tylenol) overdose.
Explanation:
Acetaminophen, a commonly used over-the-counter analgesic and antipyretic, can cause severe liver damage if taken in excessive amounts. When metabolized by the liver, acetaminophen is converted into a non-toxic form that can be safely excreted. However, a small percentage is converted into a highly reactive metabolite called N-acetyl-p-benzoquinone imine (NAPQI). In normal doses, this metabolite is neutralized by the liver’s natural antioxidant, glutathione. In cases of overdose, the liver’s glutathione stores become depleted, leading to accumulation of NAPQI. This accumulation can cause oxidative stress, cellular damage, and ultimately liver failure.
Acetylcysteine acts as a precursor to glutathione. It provides cysteine, a key building block for the synthesis of glutathione. By replenishing the liver’s glutathione levels, acetylcysteine helps neutralize the toxic metabolite (NAPQI) and prevent further liver damage. It also has a direct effect on the reduction of NAPQI. The effectiveness of acetylcysteine in preventing liver damage from acetaminophen overdose is highest when administered within 8 to 10 hours of ingestion, but it can still be beneficial if given later.
In contrast, acetylcysteine is not used for overdoses of ibuprofen, diphenhydramine, or amoxicillin. Overdoses of these substances require different treatments. For example, activated charcoal may be used to prevent further absorption of ibuprofen or diphenhydramine if administered shortly after ingestion, and specific antidotes or supportive care are used for amoxicillin toxicity.
In summary, acetylcysteine is a crucial antidote for acetaminophen overdose, leveraging its role in restoring glutathione levels to mitigate liver damage.