Which of the following drugs can impair the biotransformation of lidocaine?

Lidocaine is primarily metabolized in the liver, and its biotransformation can be affected by various drugs. Meperidine, phenytoin, and quinidine are known to have interactions that can alter the metabolism of lidocaine, leading to changes in its efficacy and safety profile.

Meperidine is an opioid analgesic that, when used concurrently with lidocaine, may inhibit the enzymes responsible for lidocaine’s metabolism, potentially increasing its plasma levels and the risk of toxicity.

Phenytoin, an anticonvulsant, has been shown to induce certain liver enzymes. This interaction can increase the clearance rate of lidocaine, which could reduce its effectiveness, especially in patients who require consistent blood levels for therapeutic efficacy.

Quinidine, an antiarrhythmic medication, can also influence lidocaine's metabolism, primarily by inhibiting some of the enzymes involved. This inhibition could lead to elevated levels of lidocaine and enhance the risk of adverse effects.

Since all three drugs can impair the biotransformation of lidocaine through different mechanisms, the correct answer encompasses all of these interactions, highlighting the complexity of polypharmacy and its impact on drug metabolism.