95% of articaine is metabolized by which enzyme?

• A. Plasma cholinesterase
• B. Liver microsomes
• C. Plasma carboxylesterase
• D. Aminotransferases

Answer: (C)

Articaine, a commonly used local anesthetic in dentistry, is primarily metabolized by plasma carboxylesterase, which accounts for about 95% of its metabolism. This enzyme is highly effective in breaking down the ester bond present in articaine's structure, leading to the formation of its metabolites.

The significance of plasma carboxylesterase in articaine metabolism stems from its widespread presence in the circulation and its efficiency in hydrolyzing ester-type local anesthetics. This action allows for rapid metabolism and clearance from the system, contributing to articaine's relatively short duration of action compared to some other local anesthetics.

Understanding the role of plasma carboxylesterase is essential for clinicians since it influences the pharmacokinetics of articaine, including its onset and duration of anesthesia. Knowledge of the metabolic pathway helps in predicting patient responses to the drug, especially in individuals with genetic variations affecting the activity of this enzyme.

The other listed enzymes, including plasma cholinesterase, liver microsomes, and aminotransferases, play different roles in drug metabolism but are not the primary agents for articaine. While plasma cholinesterase is involved in the metabolism of certain anesthetics, it is