Cytochrome P450 1A2 (CYP1A2) and Cytochrome P450 3A4 (CYP3A4) (CYP1A2 and CYP3A4)

Lidocaine metabolic enzymes primarily refer to the hepatic cytochrome P450 (CYP) system, specifically the isoforms Cytochrome P450 1A2 (CYP1A2) and Cytochrome P450 3A4 (CYP3A4), which are responsible for the majority of lidocaine biotransformation [1][2]. These enzymes catalyze the oxidative N-dealkylation of lidocaine to its primary active metabolite, monoethylglycinexylidide (MEGX), and subsequently to glycinexylidide (GX) [3]. This metabolic process is the principal route of lidocaine elimination, making the functional status of these enzymes a critical determinant of drug plasma levels and duration of action [4]. Because lidocaine has a narrow therapeutic window, any alteration in the activity of these enzymes—whether through genetic variation, liver disease, or drug-drug interactions—can lead to lidocaine accumulation and life-threatening local anesthetic systemic toxicity (LAST) [1][5]. Consequently, these enzymes are significant targets for assessing pharmacokinetic safety and potential adverse reactions in clinical settings [2]. Monitoring the production of metabolites like MEGX has also been used as a biomarker for hepatic functional reserve and to predict lidocaine clearance [4]. Drugs that inhibit these enzymes, such as cimetidine or fluvoxamine, can dangerously increase lidocaine exposure, while inducers like rifampin can reduce its efficacy [3][5].

Other names

Lidocaine-metabolizing enzymesHepatic microsomal enzymesCYP1A2CYP3A4Lidocaine metabolic enzymes

Oxidative N-dealkylation of lidocaine to monoethylglycinexylidide (MEGX) and glycinexylidide (GX), followed by further hydrolysis and hydroxylation.