What Has Lidocaine in It? Creams, Patches & More

Lidocaine shows up in a remarkably wide range of products, from drugstore numbing creams and adhesive patches to dental injections, throat sprays, sexual health products, and even intravenous cardiac medications. First synthesized by Swedish chemists Nils Löfgren and Bengt Lundqvist in 1943, it became the first amino-amide local anesthetic and quickly replaced older, less stable alternatives.¹ Today it remains one of the most widely used numbing agents in medicine, available in concentrations and delivery systems designed for almost every part of the body.

Over-the-Counter Creams, Gels, and Ointments

The lidocaine products most people encounter first are the ones sitting on pharmacy shelves. These typically contain between 2% and 5% lidocaine in a cream, gel, or ointment base. They are marketed for minor skin irritations, sunburn, insect bites, hemorrhoids, and muscle aches. Brand names vary by country, but the active ingredient is the same. When you rub one of these on your skin, the lidocaine diffuses into the outer layers and temporarily blocks nerve signals in that area, which reduces pain and itching.

A key thing to understand about topical lidocaine is that very little of it actually reaches your bloodstream. In one study testing a 5.4% topical system, the highest blood lidocaine level measured was far below toxic thresholds, and the drug delivery scaled predictably with the amount applied.² That low systemic absorption is the whole point of topical formulations: you get pain relief where you need it without flooding your body with the drug. An early patch study found that the highest blood lidocaine level reached was just 0.1 micrograms per milliliter, far below levels that cause side effects.³

Prescription Patches

Lidocaine patches are a step up from creams in terms of controlled, sustained delivery. The original 5% lidocaine patch was approved by the FDA in 1999 for pain caused by postherpetic neuralgia, the lingering nerve pain that can follow a shingles outbreak.⁴ Each 5% patch contains about 700 mg of lidocaine, but because it releases the drug slowly through the skin over a 12-hour wear period, the amount that actually enters your system stays low.

A Cochrane review pooling data from multiple studies found that topical lidocaine patches relieved postherpetic neuralgia pain better than placebo.⁵ A separate trial also showed that 5% lidocaine patches reduced pain during both rest and movement in people with acute shingles, not just the chronic nerve pain that follows it.⁶

In 2018, a newer 1.8% lidocaine topical system was approved. Despite having a much lower concentration, it delivers the same amount of lidocaine into the skin as the older 5% patch, just more efficiently. The total drug load is only 36 mg compared to 700 mg in the 5% version, a roughly 19-fold reduction, with better adhesion that keeps the patch stuck to your skin through a full 12-hour period.⁴ For patients who worry about the sheer amount of drug sitting on their skin, the newer system is a significant reassurance.

Combination Numbing Creams

Some of the most effective topical anesthetics combine lidocaine with a second numbing agent. The best-known example is a cream that blends lidocaine and prilocaine in equal parts (25 mg/g each). This combination works because the two drugs form a mixture that stays liquid at skin temperature, which helps them penetrate more deeply than either one alone.

This type of cream has been studied for decades across a range of uses. It provides pain relief equivalent to an injected local anesthetic for procedures like blood draws and IV placement, and it works for skin procedures like the removal of molluscum contagiosum lesions in children and split-skin graft harvesting in adults.⁷ It has also been studied as a way to reduce pain from needle sticks in newborns, though use in very young infants requires careful dosing because of the risk of a blood condition called methemoglobinemia, which I will come back to.⁸

Another combination product pairs lidocaine with tetracaine (7%/7%) and is FDA-approved for numbing the skin before cosmetic procedures. In a Phase 3 trial, it significantly reduced pain during hyaluronic acid filler injections compared to placebo, and most participants said they would use it again.⁹

Oral and Mucosal Products

Lidocaine also comes in forms designed for the inside of your mouth and throat. Viscous lidocaine, a thick liquid typically at 2% concentration, is swished around the mouth to numb painful ulcers, inflamed gums, or the raw tissue caused by radiation or chemotherapy.¹⁰ Lidocaine throat sprays serve a similar purpose, numbing the back of the throat before procedures like endoscopy or bronchoscopy. Lozenges and gels containing lower concentrations are sold over the counter for sore throats and teething pain, though pediatric teething products containing lidocaine have drawn safety warnings due to the risk of accidental overdose in small children.

One important caution with oral lidocaine products: because the mucous membranes of the mouth and throat absorb drugs much more readily than intact skin, blood levels can climb faster than you might expect. The case report cited above involved a patient who developed toxicity from frequent use of viscous lidocaine on a tongue ulcer. The lesson is that “topical” does not always mean “negligible absorption,” especially inside the mouth.

Dental Injections

If you have ever had a cavity filled or a tooth pulled, you have almost certainly received lidocaine. The standard dental formulation is 2% lidocaine combined with epinephrine, a drug that constricts blood vessels near the injection site. The epinephrine keeps the lidocaine concentrated in the tissue for longer, which extends the numbing effect and reduces bleeding. In head-to-head comparisons, lidocaine with epinephrine outperformed other local anesthetics for achieving reliable tooth-level numbness and produced longer-lasting anesthesia of both the tooth pulp and the surrounding soft tissue.¹¹

The concentration of epinephrine matters. A trial comparing two different epinephrine strengths in supplementary dental injections found that the higher concentration (1:80,000) achieved an 82% success rate in numbing stubborn teeth, compared to 57% for the lower concentration (1:200,000), with no meaningful difference in heart rate between the two groups.¹² This is worth knowing if you have ever been told you are “hard to numb” at the dentist: the issue is often about the delivery technique and epinephrine concentration, not about you being resistant to lidocaine itself.

Injectable Lidocaine for Nerve Blocks and Regional Anesthesia

Beyond dentistry, lidocaine is injected in clinical settings for nerve blocks, wound repairs, and minor surgeries. A nerve block involves injecting the drug near a specific nerve to temporarily shut down sensation in the area that nerve serves. Research using ultrasound-guided femoral nerve blocks estimated that a lidocaine concentration of just under 1% was enough to achieve a successful block in about nine out of ten patients.¹³ That is a remarkably low concentration, which underscores how potent lidocaine is when delivered directly to nerve tissue.

Tumescent anesthesia is another injectable lidocaine technique worth mentioning. It involves flooding the tissue beneath the skin with a very dilute lidocaine solution mixed with epinephrine and saline until the area becomes firm and swollen. Originally developed for liposuction, it has expanded into dermatologic surgery, vascular procedures, and more. Because the lidocaine is so dilute and the epinephrine slows absorption, the safe dosing limit jumps dramatically, up to 55 mg per kilogram of body weight in tumescent liposuction, compared to 4.5 mg/kg for standard infiltration and 7 mg/kg when epinephrine is added.¹⁴

Sexual Health Products

Lidocaine sprays, creams, and wipes are widely sold (both over the counter and by prescription) for men dealing with premature ejaculation. The idea is straightforward: reducing penile sensitivity delays climax. A randomized trial of a 5% lidocaine spray applied to the glans 10 to 20 minutes before intercourse found a significant improvement in ejaculatory control and intercourse frequency compared to placebo, with only mild local side effects.¹⁵

A proof-of-concept study using a combined lidocaine-prilocaine spray reported even more dramatic results: average time to ejaculation increased roughly eightfold, from about 1 minute 24 seconds to 11 minutes 21 seconds, when the spray was applied 15 minutes before intercourse.¹⁶ The practical concern with these products is transfer to a partner, which can cause unwanted numbness. Most product instructions address this by recommending the spray be applied well in advance and, in some cases, wiped off before intercourse.

Intravenous Lidocaine for Heart Rhythm Problems

Lidocaine’s uses extend well beyond numbing. Given intravenously, it acts as an anti-arrhythmic drug, meaning it can help stabilize dangerous heart rhythms. It works by blocking sodium channels in heart muscle cells in a way that raises the threshold for the heart to go into ventricular fibrillation and can interrupt life-threatening rapid rhythms driven by electrical re-entry circuits, especially in tissue damaged by a heart attack.¹⁷

For decades, IV lidocaine was the go-to drug for ventricular tachycardia and cardiac arrest. Its role has narrowed over time as newer drugs proved more effective. A randomized trial comparing IV lidocaine against amiodarone for persistent ventricular tachycardia found that amiodarone terminated the arrhythmia in 78% of patients, while lidocaine managed it in only 27%.¹⁸ Today, lidocaine is typically a second-line option when other anti-arrhythmic drugs fail or are unavailable, but it remains stocked in emergency departments and crash carts everywhere.

Safety Risks Worth Knowing About

Lidocaine is considered safe when used as directed, but “as directed” does the heavy lifting in that sentence. Problems arise when too much lidocaine enters the bloodstream, a condition called local anesthetic systemic toxicity. Early warning signs are neurological: numbness around the mouth, ringing in the ears, dizziness, and a metallic taste. At higher blood levels, seizures and cardiovascular collapse can follow.¹⁹

A rarer but serious risk is methemoglobinemia, a condition where lidocaine (or a related anesthetic) causes hemoglobin to change form so it can no longer carry oxygen effectively. A 10-year retrospective study across nearly 95,000 procedures found an overall methemoglobinemia rate of about 0.035%, though the rate was much higher for certain procedures like transesophageal echocardiography (0.25%) and bronchoscopy (0.16%).²⁰ Case reports have documented severe drops in oxygen saturation after topical lidocaine use during medical procedures.²¹ The risk climbs when lidocaine is combined with benzocaine, another topical anesthetic frequently used in spray form.²²

Pediatric Risks and Accidental Ingestion

Children are more vulnerable to lidocaine toxicity than adults, and the margin of error is smaller than many parents realize. As little as one teaspoon of a lidocaine-containing product can cause serious toxicity in a young child, including depressed consciousness, seizures, and in extreme cases, death.²³ The reduced muscle mass of infants and toddlers means their bodies absorb the drug more quickly after accidental exposure, and the drug has fewer places to distribute itself away from the brain and heart.²⁴

A French pharmacovigilance analysis identified 64 cases of local anesthetic toxicity in children, with lidocaine alone responsible for nearly half of them. Over a third of those cases were life-threatening, and two children died. Doses exceeded recommendations in about 40% of cases, but troublingly, even recommended doses sometimes led to severe outcomes.²⁵ The practical takeaway: keep any lidocaine cream, gel, or liquid locked away from children, just as you would a prescription medication. A tube of numbing cream left on a bathroom counter is an ingestion hazard.

How Your Liver Processes Lidocaine

Your liver is almost entirely responsible for clearing lidocaine from your blood, primarily through a specific enzyme system. Research has shown that blocking this enzyme pathway reduced lidocaine clearance by about 60% in healthy people and 44% in patients with mild liver problems. In people with severe liver dysfunction, clearance was already so compromised that blocking the enzyme made little additional difference.²⁶

This has real implications. If you have liver disease, or if you take medications that compete for the same liver enzymes (certain antibiotics, antifungals, and heart medications are common culprits), lidocaine can build up in your blood faster than expected. That is true even for topical products if you are using them over large areas of skin or for extended periods. Doctors and pharmacists typically adjust lidocaine dosing or monitoring for patients with known liver issues, but it is worth mentioning your liver health proactively if you are prescribed any lidocaine product beyond a small OTC tube.

Veterinary Uses

Lidocaine is not just a human drug. It is one of the most commonly used local anesthetics in veterinary medicine, administered to everything from dogs and cats to horses and cattle. In large-animal practice, caudal epidural lidocaine is a standard technique for procedures on the tail end of cattle. A study comparing lidocaine alone, xylazine alone, and the two combined found that lidocaine provided the fastest onset of numbness, taking about five minutes, but the shortest duration at roughly 82 minutes. Combining lidocaine with xylazine extended pain relief to about five hours while preserving the quick onset.²⁷ The versatility that makes lidocaine useful in human medicine translates directly into animal care, where the same properties of rapid onset, predictable duration, and a well-understood safety profile make it a first-choice anesthetic across species.