- Lidocaine/prilocaine
Lidocaine/prilocaine is a eutectic mixture of equal quantities (by weight) of
lidocaine andprilocaine . A 5%emulsion preparation, containing 2.5% each of lidocaine/prilocaine, is marketed byAstraZeneca under thetrade name EMLA (an abbreviation for eutectic mixture of local anesthetic)."Lidocaine/prilocaine" is also available as a non-brand generic drug. Walgreens dispenses it in a version manufactured by Fougera.
Eutectic mixture
Separately, lidocaine and prilocaine are solid bases. When mixed together in equal quanitites by weight, however, they form a eutectic mixture – that is the
melting point of the mixture is lower than the melting points of the individual components. The lidocaine/prilocaine eutectic mixture is an oil with a melting point of 16°C, thus can be formulated into preparations without the use of a non-aqueous solvent. This allows higher concentrations of anaesthetic to be formulated into the preparation and maintained during application.Clinical use
Indications
The lidocaine/prilocaine combination is indicated for
dermal anaesthesia . Specifically it is applied to prevent pain associated withintravenous catheter insertion, blood sampling, superficial surgical procedures; and topical anaesthesia of leg ulcers for cleansing or debridement. Also, it can be used to numb the skin before tattooing as well as laser hair removal.Dosage forms
Lidocaine/prilocaine eutectic mixture is marketed as a 5% oil-in-water emulsion incorporated in a cream base (EMLA cream) or a cellulose disk (EMLA patch). The cream is applied under an
occlusive dressing , while the patch incorporates an occlusive dressing to facilitate absorption of lidocaine and prilocaine into the area where anaesthesia is required. Local dermal anaesthesia is achieved after approximately 60 minutes, whereupon the occlusive dressing (or patch) is removed. The duration of anaesthesia is approximately two hours following removal of the occlusive dressing.Emla Cream
EMLA (Eutectic Mixture of Lidocaine and Prilocaine) is a local anaesthetic for topical application, developed to anaesthetise intact skin.EMLA is used to prevent pain associated with needle insertion, intravenous cannulation, and superficial surgery on skin and genital mucous membrane. It can also be used to relieve and prevent pain associated with the cleansing and treatment of leg ulcers.
See also
*
Eutectic point
*Lidocaine
*Prilocaine External links
* [http://www.ihateneedles.co.uk/ Emla Product Information]
* [http://www.astrazeneca-us.com/pi/EMLA.pdf AstraZeneca product information]
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