Comparative Pharmacology
Head-to-head clinical analysis: EMLA versus XYLOCAINE 4 PRESERVATIVE FREE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EMLA versus XYLOCAINE 4 PRESERVATIVE FREE.
EMLA vs XYLOCAINE 4% 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 stabilizes the neuronal membrane by inhibiting sodium ion influx through voltage-gated sodium channels, thereby blocking the initiation and propagation of action potentials, resulting in local anesthesia.
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.
Maximum 4.5 mg/kg (not to exceed 300 mg) via subcutaneous infiltration, epidural, or nerve block; repeat dosing after 30 minutes if needed.
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.
Terminal elimination half-life: ~1.5–2 hours (adults). Prolonged in hepatic impairment, congestive heart failure, or neonates.
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 (mostly 4-hydroxy-2,6-xylidine and conjugates); <10% unchanged. Biliary/fecal: minor.
Category C
Category C
Local Anesthetic
Local Anesthetic