EMLA (Eutectic Mixture of Local Anesthetics) is a eutectic mixture of lidocaine 2.5% and prilocaine 2.5% formulated as an oil in water emulsion developed to anesthetise intact skin. This eutectic mixture has a melting point below room temperature and therefore both local anesthetics exist as a liquid oil rather than as crystals. EMLA Cream is indicated as a topical anesthetic for use on:1) normal intact skin for local analgesia; and 2) genital mucous membranes for superficial minor surgery and as pretreatment for infiltration anesthesia. To provide sufficient analgesia for clinical procedures such as intravenous catheter placement and venipuncture, EMLA Cream should be applied under an occlusive dressing for at least 1 hour. To provide dermal analgesia for clinical procedures such as split skin graft harvesting, EMLA Cream should be applied under occlusive dressing for at least 2 hours. Satisfactory dermal analgesia is achieved 1 hour after application, reaches maximum at 2 to 3 hours, and persists for 1 to 2 hours after removal. Absorption from the genital mucosa is more rapid and onset time is shorter (5 to 10 minutes) than after application to intact skin.
EMLA Cream is contraindicated in patients with a known history of sensitivity to local anesthetics of the amide type (lidocaine, mepivacaine, prilocaine, bupivacaine, ropivacaine). Patients treated with class III anti-arrhythmic drugs (eg, amiodarone, bretylium, sotalol, dofetilide) should be under close surveillance and ECG monitoring considered, because cardiac effects may be additive. Studies in laboratory animals have shown that EMLA Cream has an ototoxic effect when instilled into the middle ear. Prilocaine’s metabolite, o-toluidine, can cause methemoglobinemia. EMLA Cream should not be used in patients with congenital or idiopathic methemoglobinemia and in infants under the age of twelve months who are receiving treatment with methemoglobin-inducing agents. There have been reports of significant methemoglobinemia (20-30%) in infants and children following excessive applications of EMLA Cream. Neonates and infants up to 3 months of age should be monitored for Met-Hb levels before, during, and after the application of EMLA Cream.
EMLA Cream: Precautions/Contraindications
- Allergy to amide anesthestics
- Patients treated with class III anti-arrhythmic drugs (eg, amiodarone, bretylium, sotalol, dofetilide)
- Patients with congenital or idiopathic methemoglobinemia
- Infants under the age of twelve months who are receiving treatment with methemoglobin-inducing agents