Comparative Pharmacology
Head-to-head clinical analysis: EMLA versus MARCAINE HYDROCHLORIDE PRESERVATIVE FREE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EMLA versus MARCAINE HYDROCHLORIDE PRESERVATIVE FREE.
EMLA vs MARCAINE 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.
Bupivacaine blocks sodium ion channels in nerve cell membranes, preventing the generation and conduction of nerve impulses, 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.
Local infiltration: up to 30 mL of 0.5% (150 mg) per dose. Peripheral nerve block: 30-40 mL of 0.5% (150-200 mg). Epidural: 15-20 mL of 0.5% (75-100 mg). Maximum single dose: 2.5 mg/kg (225 mg for 90 kg). Repeat doses after 3 hours, max 400 mg/24h.
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 in adults: 2.7 ± 1.2 hours (range 1.5-5.5 hours). In neonates, half-life is prolonged to approximately 8.1 ± 8.2 hours due to immature hepatic and renal function.
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.
Primarily hepatic metabolism to 2,6-pipecoloxylidide (PPX) and subsequent renal excretion. Renal excretion of unchanged bupivacaine accounts for approximately 5-10% of the dose. The remainder is eliminated as metabolites (PPX and others) in urine. Fecal excretion is negligible.
Category C
Category C
Local Anesthetic
Local Anesthetic