EMLA cream

EMLA Cream is a topical anesthetic used to numb the skin before certain medical procedures, such as needle insertion, skin grafts, and minor surgery. The name EMLA is an acronym for Eutectic Mixture of Local Anesthetics. This cream is a combination of two active ingredients, lidocaine and prilocaine, which work by temporarily blocking the pathway of pain signals along nerves.

Composition and Mechanism of Action

EMLA cream contains a eutectic mixture of 2.5% lidocaine and 2.5% prilocaine. The term "eutectic" refers to a unique mixture of two substances that have a lower melting point than either of the individual components. This property allows EMLA cream to become more readily absorbed into the skin, enhancing its analgesic effect.

Lidocaine and prilocaine are both local anesthetics that inhibit sodium influx through sodium channels in the neuronal membrane. This inhibition blocks the initiation and conduction of nerve impulses, leading to a loss of sensation in the area where the cream is applied.

Indications

EMLA cream is indicated for use on normal intact skin for local analgesia in various procedures, including:

• Venipuncture
• Intravenous cannulation
• Laser hair removal
• Minor skin surgeries

It is also used to numb the genital skin before minor surgeries, including adult male circumcision, and in the treatment of minor conditions like lichen sclerosus. Additionally, EMLA cream is used in children to reduce the pain of needle procedures such as vaccinations.

Application

The cream should be applied to the skin in a thick layer without rubbing, covered with an occlusive dressing, and left in place for at least one hour before the procedure. The duration of application can be extended up to two hours for procedures involving thicker skin, such as on the sole of the foot, to ensure adequate analgesia.

Side Effects

Common side effects of EMLA cream include temporary skin reactions at the site of application, such as:

• Redness
• Swelling
• Pale skin
• Initial burning or itching sensation

Rarely, more serious side effects can occur, including systemic toxicity if applied over a large area of broken skin, leading to elevated blood levels of the active ingredients.

Contraindications

EMLA cream should not be used in patients with a known hypersensitivity to lidocaine, prilocaine, or any other amide-type local anesthetics. It is also contraindicated in patients with methemoglobinemia, a rare blood disorder, or those taking drugs that induce methemoglobinemia.