Lidocaine/prilocaine is a eutectic mixture of equal quantities (by weight) of

lidocaine Lidocaine, also known as lignocaine and sold under the brand name Xylocaine among others, is a local anesthetic of the amino amide type. It is also used to treat ventricular tachycardia. When used for local anaesthesia or in nerve blocks, li ...

and

prilocaine Prilocaine () is a local anesthetic of the amino amide type first prepared by Claes Tegner and Nils Löfgren. In its injectable form (trade name Citanest), it is often used in dentistry. It is also often combined with lidocaine as a topical p ...

. A 5%

emulsion An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Althou ...

preparation, containing 2.5% each of lidocaine/prilocaine, is marketed by APP Pharmaceuticals under the

trade name A trade name, trading name, or business name, is a pseudonym used by companies that do not operate under their registered company name. The term for this type of alternative name is a "fictitious" business name. Registering the fictitious name ...

EMLA (an abbreviation for ''Eutectic Mixture of Local Anesthetics''). As a spray, it is marketed under the name Tempe (topical eutectic-like mixture for premature ejaculation) (PSD502) that can be used by men to help with

premature ejaculation Premature ejaculation (PE) occurs when a man expels semen (and most likely experiences orgasm) soon after beginning sexual activity, and with minimal penile stimulation. It has also been called ''early ejaculation'', ''rapid ejaculation'', '' ...

. The spray is manufactured by Plethora Solutions and branded as Fortacin in the UK and Recordati in the EU.

Eutectic mixture

Separately, lidocaine and prilocaine are solid bases. When mixed in equal quantities by weight, however, they form a eutectic mixture – that is the

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...

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 18 °C, and can be formulated into preparations without the use of a non-

aqueous An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would ...

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 Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), am ...

. Specifically it is applied to prevent pain associated with intravenous

catheter In medicine, a catheter (/ˈkæθətər/) is a thin tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. Cat ...

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 electrolysis and laser hair removal. It is also sometimes used in advance of injected local anaesthetics for minor surgery and biopsies. A topical spray consisting of an aerosol formulation of lidocaine and prilocaine was evaluated under the name PSD502 for use in treating

. The spray is applied on the penile skin prior to intercourse. While this formulation was not approved by the FDA, a similar product, Promescent, is available

over-the-counter Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid prescr ...

in the U.S.

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. E. Fougera & Co., makers of the generic cream widely used in the United States as Lidocaine and Prilocaine Cream, 2.5%/2.5%, recommends different timing for application of the cream as well as length of anesthesia. They state the cream must be applied at least one hour before the start of a routine procedure and for two hours before the start of a painful procedure. Additionally, they state that the duration of effective skin anesthesia will be at least one hour after removal of the occlusive dressing.

Circumcision

Lidocaine/prilocaine eutectic mixture has been used during

circumcision Circumcision is a procedure that removes the foreskin from the human penis. In the most common form of the operation, the foreskin is extended with forceps, then a circumcision device may be placed, after which the foreskin is excised. Topic ...

in newborn boys and has been considered efficacious and safe to lessen pain from circumcision. The European Medicines Agency concludes in its latest (2014) statement on Emla: "Safety and efficacy for the use of EMLA on genital skin and genital mucosa have not been established in children younger than 12 years. Available paediatric data do not demonstrate adequate efficacy for circumcision." The Patient Information Leaflet of EMLA in the UK states: "EMLA Cream should not be applied to the genital skin (e.g. penis) and genital mucosa (e.g. in the vagina) of children (below 12 years of age) owing to insufficient data on absorption of active substances."

Tempe

The spray is a combination of local

anaesthetic An anesthetic (American English) or anaesthetic (British English; see spelling differences) is a drug used to induce anesthesia ⁠— ⁠in other words, to result in a temporary loss of sensation or awareness. They may be divided into ...

and

in a metered-dose

aerosol An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of ant ...

that is sprayed directly on the penis to numb sensations. It was developed by the same group that invented the erectile dysfunction drug

sildenafil Sildenafil, sold under the brand name Viagra, among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension. It is unclear if it is effective for treating sexual dysfunction in women. It is taken by m ...

. The drug was approved in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...

and was released in the UK market in November 2016 and within the EU will be marketed by, early in 2017 In the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

, the

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

(FDA) is expected to approve the drug in 2018.

Compendial status

United States Pharmacopeia The ''United States Pharmacopeia'' (''USP'') is a pharmacopeia (compendium of drug information) for the United States published annually by the United States Pharmacopeial Convention (usually also called the USP), a nonprofit organization tha ...

References

External links

* {{DEFAULTSORT:Lidocaine Prilocaine Local anesthetics Combination drugs AstraZeneca brands Products introduced in 2013