Comparative Pharmacology
Head-to-head clinical analysis: EMLA versus PROCAINE HYDROCHLORIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EMLA versus PROCAINE HYDROCHLORIDE.
EMLA vs PROCAINE 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.
Blocks voltage-gated sodium channels, inhibiting nerve impulse conduction by stabilizing the neuronal membrane and preventing depolarization.
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: 0.5% solution, up to 200 mg (40 mL) per dose. Nerve block: 0.5% solution, 100-200 mg (20-40 mL) per dose. Intravenous regional anesthesia (Bier block): 0.5% solution, 50-100 mg (10-20 mL) per dose. Maximum total dose: 200 mg without epinephrine, 250 mg with epinephrine 1:200,000.
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 is approximately 7.7 minutes in adults with normal hepatic function. This short half-life reflects rapid hydrolysis by plasma pseudocholinesterases. In patients with pseudocholinesterase deficiency, half-life may be prolonged to 20-30 minutes.
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 renal excretion of metabolites (para-aminobenzoic acid and diethylaminoethanol) and unchanged drug. Approximately 80% of a dose is excreted in urine as para-aminobenzoic acid and conjugates; <2% excreted unchanged. Biliary/fecal elimination is negligible.
Category C
Category C
Local Anesthetic
Local Anesthetic