EMLA cream is a topical numbing cream that contains two local anesthetics, lidocaine (2.5%) and prilocaine (2.5%), blended together to temporarily block pain signals from the skin. It’s applied directly to the skin surface before medical procedures to reduce or eliminate pain from needle sticks, minor surgeries, and other treatments that would otherwise hurt.
The name “EMLA” stands for Eutectic Mixture of Local Anesthetics. “Eutectic” refers to the way the two ingredients are combined: when mixed at specific proportions, lidocaine and prilocaine form a liquid at room temperature even though each one is a solid on its own. This liquid form penetrates the skin more effectively than either ingredient could alone.
How EMLA Numbs the Skin
Both lidocaine and prilocaine work by blocking nerve cells in the skin from firing pain signals. Normally, when a needle pierces your skin, nerve endings open tiny channels that allow charged particles to rush in, creating an electrical signal that travels to your brain and registers as pain. The anesthetics in EMLA temporarily shut those channels down, so even though the tissue is being disturbed, the nerves can’t generate the signal. You feel pressure but not sharp pain.
Because the cream sits on top of the skin rather than being injected underneath it, it needs time to soak through the outer layers and reach the nerve endings below. This is why EMLA requires advance planning: you apply it well before the procedure, not right when it starts.
Common Uses
EMLA is FDA-approved for use on intact skin and on genital mucous membranes. The most common everyday use is numbing skin before needle procedures like blood draws, IV placement, or vaccinations, especially in children. It’s also used before cosmetic and dermatological treatments such as laser hair removal, wart removal, and skin graft harvesting.
In genital procedures, EMLA serves as either the primary numbing agent for minor surface-level work (like removing genital warts) or as a first step before a deeper local anesthetic injection. For female genital mucous membranes, it can provide enough numbness for minor procedures on its own. For male genital skin, it’s typically used to reduce the sting of a follow-up anesthetic injection.
How to Apply It
EMLA works best when applied in a thick layer and covered with an airtight dressing, often a simple adhesive bandage or plastic wrap taped at the edges. The covering traps moisture and heat, which helps the cream absorb more deeply into the skin. Without it, the cream dries out and doesn’t penetrate as well.
The general guideline is about 1 gram of cream per 10 square centimeters of skin, roughly the size of a large postage stamp. For minor needle procedures, you typically apply the cream 60 minutes before the procedure. More involved procedures on larger areas of skin may call for longer application times, sometimes up to two hours. On genital mucous membranes, the wait time is shorter because the tissue is thinner and absorbs the anesthetic faster.
After the recommended time, you remove the dressing and wipe the cream off. The numbing effect doesn’t disappear the moment the cream comes off. Skin typically stays numb for an additional one to two hours, giving a comfortable window for the procedure.
Side Effects
The most common reactions are local and mild. You may notice temporary skin paleness (blanching) at the application site, which happens because the anesthetics cause small blood vessels to constrict. Redness, slight swelling, or a mild burning or itching sensation when the cream is first applied are also normal. Small bruise-like spots (purpura) can appear in some people. These effects resolve on their own once the cream is removed and the numbness wears off.
Rare but Serious Risks
The most significant risk with EMLA is a blood condition called methemoglobinemia, caused primarily by the prilocaine component. In this condition, the oxygen-carrying molecule in red blood cells gets altered so it can no longer deliver oxygen efficiently. Early signs include bluish discoloration of the lips or fingertips and a general feeling of being unwell. At higher levels, blood can take on a chocolate-brown color.
This reaction is rare when EMLA is used as directed on small areas of intact skin. The risk increases substantially when the cream is applied over large areas, left on for longer than recommended, used on broken or irritated skin (eczema, psoriasis, open wounds), or used repeatedly in a short period. Damaged skin absorbs the anesthetics much faster, which can push blood levels into a dangerous range. One published case report documented serious systemic toxicity in a patient who applied EMLA to a leg ulcer, where the compromised skin barrier allowed rapid absorption.
Seizures from lidocaine absorption are another rare possibility, again primarily when large amounts are applied to damaged skin or when the cream is used with other medications that affect the same pathways.
Who Should Avoid EMLA
EMLA should not be used on broken, inflamed, or infected skin. People with a known sensitivity to lidocaine, prilocaine, or other local anesthetics in the same family should avoid it. Those with conditions that already affect how their blood carries oxygen, such as congenital methemoglobinemia or glucose-6-phosphate dehydrogenase (G6PD) deficiency, face a higher risk of the oxygen-related side effects described above.
Certain medications can increase the chance of methemoglobinemia when combined with EMLA. If you take other drugs that are known to affect hemoglobin, including some anti-inflammatory medications, mention this before EMLA is used.
Use in Children
EMLA is widely used in pediatric settings to take the sting out of blood draws and IV placements. However, dosing limits for children are stricter than for adults, based on age and weight. Infants under three months old are at the highest risk for methemoglobinemia because their blood chemistry handles the prilocaine metabolite less efficiently than an older child’s or adult’s. For very young infants, both the amount of cream and the area of skin it covers are tightly restricted.
Parents are sometimes given EMLA tubes to apply at home before a clinic visit, with instructions on exactly how much to use and when to put it on so the timing lines up with the appointment.
Prescription vs. Over-the-Counter
In the United States, EMLA cream is available by prescription. Your doctor or clinic may apply it on-site before a procedure, or they may write a prescription for you to pick up at a pharmacy and apply at home beforehand. In some other countries, including the United Kingdom, lower-strength lidocaine and prilocaine creams can be purchased over the counter at pharmacies without a prescription, though the EMLA brand itself may still require one depending on the formulation and pack size.
Generic versions containing the same 2.5%/2.5% lidocaine-prilocaine combination are also available in many markets, typically at a lower cost than the brand-name product. These generics contain the same active ingredients and work the same way.