Comparative Pharmacology
Head-to-head clinical analysis: EMLA versus LIDOCAINE HYDROCHLORIDE PRESERVATIVE FREE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EMLA versus LIDOCAINE HYDROCHLORIDE PRESERVATIVE FREE.
EMLA vs LIDOCAINE HYDROCHLORIDE PRESERVATIVE FREE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
EMLA is a eutectic mixture of lidocaine 2.5% and prilocaine 2.5%. Lidocaine and prilocaine are amide-type local anesthetics that block sodium ion channels in neuronal membranes, inhibiting the initiation and conduction of nerve impulses, thereby producing local analgesia.
Lidocaine is a local anesthetic that stabilizes the neuronal membrane by inhibiting sodium ion channels, thereby blocking the initiation and conduction of nerve impulses. It also exhibits cardiac effects as a class IB antiarrhythmic agent by modulating sodium channels in myocardial cells.
Apply a thick layer of cream (approximately 2.5 g per 20 cm²) to intact skin under an occlusive dressing for at least 1 hour for minor procedures; for dermal procedures on larger areas, apply up to 60 minutes before procedure, maximum single application area of 600 cm² in adults.
1-4 mg/kg via intravenous bolus, not to exceed 300 mg; may be followed by continuous infusion of 1-4 mg/min.
None Documented
None Documented
After topical application, the terminal elimination half-life of lidocaine is approximately 1.5-2 hours; prilocaine half-life is approximately 1.5 hours. In neonates, half-life may be prolonged due to immature hepatic function. Clinical context: Steady state is achieved within 12-24 hours with repeated application.
1.5–2 hours (terminal) in healthy adults; prolonged in hepatic impairment (up to 5–7 hours), heart failure (up to 10 hours), or with continuous infusion (>24 h) due to accumulation. Context: requires monitoring in hepatic or cardiac dysfunction to avoid toxicity.
Lidocaine and prilocaine are metabolized in the liver; lidocaine metabolites (primarily 4-hydroxyxylidine) and prilocaine metabolites (primarily o-toluidine) are excreted renally. Less than 5% of unchanged lidocaine and prilocaine are excreted unchanged in urine. Fecal excretion is negligible.
Renal: ~90% as metabolites (primarily monoethylglycinexylidide [MEGX] and glycinexylidide [GX]), <10% unchanged. Fecal: <1%.
Category C
Category A/B
Local Anesthetic
Local Anesthetic / Antiarrhythmic (Class Ib)