Emla
Mechanism :
EMLA (Eutectic Mixture of Local Anesthetics) is a 1:1 oil/water emulsion of a eutectic mixture of lidocaine and prilocaine bases. Lidocaine and prilocaine are both amide-type local anesthetic agents. They stabilize the neuronal membrane preventing the initiation and conduction of nerve impulses, thereby effecting local anesthetic action. EMLA provides dermal analgesia; the depth of which depends upon the application time and the applied dose. Analgesia may be less for deeper structures.
Indication :
- Topical analgesia of intact skin
- Topical analgesia of genital mucosa
Contraindications :
Patients who are hypersensitive to local anesthetics of the amide type or to any other component of the product; with congenital or idiopathic methemoglobinemia; who are less than 6 months of age, until further clinical data are available; children between 6 to 12 months requiring treatment with methemoglobin-inducing agents e.g., sulfonamides.
Dosing :
Available as a cream containinglidocaine 2.5% and
prilocaine 2.5%.
<3 months, <5 kg:
Do not exceed 1 g total dose/application area >10 cm²/>1 hour application time.
3-12 months and >5 kg:
Do not exceed 2 g total dose/application area >20 cm²/>4 hours application time.
1-6 years and >10 kg:
Do not exceed 10 g total dose/application area >100 cm²/>4 hours application time.
7-12 years and >20 kg:
Do not exceed 20 g total dose/application area >200 cm²/>4 hours application time.
Adverse Effect :
Transient local reactions such as paleness, erythema and edema, mild burning or itching sensation, alterations in temperature sensations.
Interaction :
Prilocaine: Accentuates the formation of methemoglobin (MetHb) by a mechanism involving metabolism of prilocaine to o-toluidine and subsequent oxidation of hemoglobin to MetHb. In infants below the age of 3 months, the MetHb reductase levels are lower than in older children and in adults. In these infants and in patients treated with other drugs known to induce methemoglobinemia, i.e., sulfonamides, EMLA may induce the formation of methemoglobin and result in overt clinical signs of methemoglobinemia.
Large doses of EMLA: Risk of systemic toxicity in patients receiving other local anesthetics or agents structurally related to amide-type local anesthetics since the toxic effects are additive.
Hepatic Dose :
Smaller areas of treatment are recommended for patients with severe hepatic impairment.