Comparative Pharmacology
Head-to-head clinical analysis: EMLA versus PRILOCAINE HYDROCHLORIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EMLA versus PRILOCAINE HYDROCHLORIDE.
EMLA vs PRILOCAINE HYDROCHLORIDE
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.
Prilocaine hydrochloride is an amino amide local anesthetic that reversibly blocks sodium channels in nerve cell membranes, inhibiting nerve impulse propagation.
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.
Adults: 4 mg/kg (max 200 mg) via infiltration or nerve block; may repeat after 2 hours with 50% of initial dose.
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 half-life: 1.5-2 hours (adults, normal hepatic function). Prolonged in neonates (up to 8-12 hours) due to immature hepatic metabolism and reduced clearance; may cause methemoglobinemia. Hepatic impairment increases half-life.
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: ~95% as metabolites (primarily o-toluidine and 4-hydroxy-2-methylaniline) and <5% unchanged. Biliary/fecal: minimal (<2%).
Category C
Category C
Local Anesthetic
Local Anesthetic