A 23-year-old asian female is brought to the ER after having a progressive jerky body movement. She has a history of seizures and takes phenytoin. She does not use tobacco, alcohol or illicit drugs. A new medication recently is prescribed after evaluation of pre-employment skin test result.An imaging shows no abnormalities. On physical examination, no focal abnormalities are noted. Blood tests reveal her plasma phenytoin level to be low. She states that she has been compliant with her medication. Which of the following drugs may be responsible for this patient's condition if co-administered with phenytoin?

Question

A 23-year-old asian female is brought to the ER after having a progressive jerky body movement. She has a history of seizures and takes phenytoin.  She does not use tobacco, alcohol or illicit drugs. A new medication recently is prescribed after evaluation of pre-employment skin test result.An imaging shows no abnormalities. On physical examination, no focal abnormalities are noted.  Blood tests reveal her plasma phenytoin level to be low.  She states that she has been compliant with her medication.  Which of the following drugs may be responsible for this patient's condition if co-administered with phenytoin?

Quizplus · Accepted Answer

Eductional Objective: Phenytoin metabolism depends on the function of hepatic P450 oxidases and is dose-dependent. Drugs that induce hepatic microsomal enzymes (phenobarbital, carbamazepine, and rifampin) enhance phenytoin metabolism and decrease its serum concentration.

A 23-Year-Old Asian Female Is Brought to the ER After