Comparative Pharmacology
Head-to-head clinical analysis: EMLA versus LIDOCAINE HYDROCHLORIDE AND EPINEPHRINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EMLA versus LIDOCAINE HYDROCHLORIDE AND EPINEPHRINE.
EMLA vs LIDOCAINE HYDROCHLORIDE AND EPINEPHRINE
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 a sodium channel blocker that stabilizes neuronal membranes and inhibits action potentials, providing local anesthesia. Epinephrine is an alpha- and beta-adrenergic agonist that causes vasoconstriction, prolonging lidocaine's effect and reducing systemic absorption.
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 anesthesia: 1% or 2% solution with epinephrine 1:100,000 or 1:200,000; maximum dose 7 mg/kg lidocaine (500 mg) in adults; administer by infiltration or nerve block, not to exceed 1 hour between doses.
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: terminal elimination half-life is approximately 1.5–2.0 hours. With continuous infusion or hepatic impairment, half-life may be prolonged (up to 4–6 hours). Epinephrine: plasma half-life is about 2–3 minutes due to rapid uptake and metabolism.
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.
Lidocaine is primarily metabolized in the liver; approximately 90% of a dose is excreted in the urine as metabolites (including monoethylglycinexylidide and glycinexylidide), with less than 10% excreted unchanged. Epinephrine is metabolized by catechol-O-methyltransferase and monoamine oxidase, with metabolites excreted in urine.
Category C
Category A/B
Local Anesthetic
Local Anesthetic / Antiarrhythmic (Class Ib)