Comparative Pharmacology
Head-to-head clinical analysis: EMLA versus SYNERA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EMLA versus SYNERA.
EMLA vs SYNERA
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 an amide-type local anesthetic that stabilizes neuronal membranes by inhibiting sodium ion influx, thereby blocking nerve impulse initiation and conduction. Tetracaine is an ester-type local anesthetic that similarly inhibits sodium channels. The combination provides local dermal 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.
Apply 1 patch (70 mg lidocaine and 70 mg tetracaine) to intact skin over the intended venipuncture site or superficial dermatologic procedure site 20-30 minutes prior to procedure; maximum 1 patch per procedure.
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.
Lidocaine: 1.5–2 hours; prilocaine: 1–1.5 hours. Terminal half-life similar for both. Note: prolonged in hepatic impairment 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 excretion of lidocaine and prilocaine metabolites: lidocaine <10% unchanged, prilocaine negligible unchanged. Metabolites primarily renal.
Category C
Category C
Local Anesthetic
Local Anesthetic