Lidocaine cream is a widely used topical medication that belongs to a class of drugs known as local anesthetics. It is specifically formulated to be applied directly to the skin, where its primary function is to cause a temporary loss of sensation. This numbing effect is achieved by blocking the transmission of pain signals in the underlying nerves. The cream is an accessible option for managing discomfort, with various concentrations available over-the-counter or by prescription.
How Lidocaine Cream Provides Relief
Lidocaine is an amide-type local anesthetic that works by stabilizing the neuronal membrane within the nerve cells. This stabilization prevents the rapid electrical changes necessary for a nerve impulse to travel.
The core mechanism involves voltage-gated sodium channels, which are like tiny gates on the surface of nerve cells. When a pain signal is initiated, these channels normally open to allow a rapid influx of sodium ions, which generates an electrical signal that moves toward the brain. Lidocaine molecules enter the nerve cell and physically block these sodium channels from the inside.
By inhibiting the influx of sodium ions, lidocaine effectively prevents the nerve cell from depolarizing, or firing its electrical signal. This interruption stops the initiation and conduction of the nerve impulse, meaning the pain message never reaches the brain for interpretation. The result is a localized and temporary numbing of the treated area.
Common Conditions Treated
Lidocaine cream provides temporary relief for various minor skin irritations. Over-the-counter formulations are frequently applied to soothe the discomfort associated with minor cuts, scrapes, and abrasions. They also alleviate the burning and itching sensation from insect bites, minor burns, and mild sunburns.
Higher-concentration or prescription-strength lidocaine creams are often used to numb the skin before medical or cosmetic procedures. This includes injections, venipuncture (blood draws), or the insertion of intravenous lines. It is also applied before cosmetic treatments like waxing, tattooing, or certain laser procedures to minimize procedural discomfort.
Lidocaine cream is also an effective tool for managing specific localized pain syndromes. It is sometimes used off-label or in prescription forms for pain associated with post-herpetic neuralgia, which is chronic nerve pain that can persist after a shingles outbreak. The numbing properties also offer symptomatic relief for anal and rectal discomfort, such as the pain and itching caused by hemorrhoids or other localized irritations.
Guidelines for Safe Application
To ensure effectiveness and safety, wash your hands thoroughly with soap and water both before and immediately after applying the medication. The cream should be applied only as a thin layer to the affected area of intact skin, unless a healthcare provider specifically instructs otherwise.
Do not rub the cream vigorously into the skin; simply spread a sufficient amount to cover the area. Avoid applying the cream to large areas of the body simultaneously, as this increases the risk of excessive absorption. If the cream is being used for a procedure, it typically needs to be applied 30 to 60 minutes beforehand to allow the numbing effect to fully develop.
Keep the cream away from sensitive mucous membranes, including the eyes, mouth, and nose, as well as any broken, cut, or severely irritated skin. The numbing effect may persist for up to 90 minutes after the cream is removed, so care should be taken to prevent accidental injury to the desensitized area during this time.
Understanding Potential Side Effects and Risks
While generally safe when used as directed, lidocaine cream can cause common, localized side effects. These reactions typically occur at the application site and may include temporary redness, mild itching, or a slight burning sensation. The skin may also appear paler or slightly swollen, but these effects are usually mild and resolve quickly once the cream is removed.
The primary safety concern with topical lidocaine is the risk of systemic toxicity, which occurs when too much of the medication is absorbed into the bloodstream. Toxicity is often caused by applying the cream to large areas of the body, using excessive amounts, or covering the area with occlusive bandages or heat, which can accelerate absorption. Signs of systemic toxicity affect the central nervous system and may initially include dizziness, lightheadedness, or confusion.
More severe symptoms involve blurred vision, ringing in the ears, slurred speech, or a metallic taste in the mouth. In rare cases, systemic toxicity can lead to seizures or irregularities in heart rhythm, such as a slow or irregular heartbeat. If any of these signs develop, the cream should be immediately removed and medical attention sought without delay.