Topical Analgesics: Lidocaine, Capsaicin, and NSAID Gels Explained

What Are Topical Analgesics and Why Do They Work?

When you ache from a sore knee, a stiff neck, or nerve pain after shingles, swallowing a pill isn’t always the best option. That’s where topical analgesics come in. These are creams, gels, or patches you apply directly to your skin to block pain where it hurts-without flooding your whole body with medicine. They’re not magic, but they work differently than pills, and that makes them safer for many people.

Unlike oral painkillers that go through your stomach, liver, and kidneys, topical analgesics stay mostly where you put them. Studies show that when you rub on a diclofenac gel, the drug concentration in your joint tissue can be 10 to 100 times higher than in your blood. That means more pain relief at the source, and far less risk of stomach upset, kidney damage, or liver stress.

There are three main types you’ll find in pharmacies and clinics: lidocaine patches, capsaicin patches, and NSAID gels. Each works in its own way. Some block nerves. Some burn you out of pain. Others quiet inflammation. Knowing how they differ helps you pick the right one for your pain.

Lidocaine Patches: The Nerve Blocker

Lidocaine is a local anesthetic you’ve probably heard of from dentists. In patch form, it’s used for nerve pain like postherpetic neuralgia-the burning, shooting pain that lingers after shingles. The standard patch is 5% lidocaine, worn for 12 hours, then taken off for 12 hours. You can use up to three patches a day, but no more.

How does it work? Lidocaine blocks sodium channels in nerve endings. Think of it like turning off a switch that sends pain signals to your brain. It doesn’t heal the nerve, but it stops the noise. A 2018 Cochrane Review found that for postherpetic neuralgia, lidocaine patches have a number needed to treat (NNT) of 6.7. That means about 7 people need to use it for one person to get meaningful relief.

Side effects are mild: about 5 to 15% of users get redness or itching where the patch is applied. But because only about 63 mg of lidocaine enters the bloodstream over 12 hours-far below dangerous levels-it’s safe even for older adults or those on multiple medications. No drug interactions. No liver burden. Just quiet relief.

Capsaicin Patches: The Burn-and-Reset Tool

If lidocaine is a mute button, capsaicin is a reset switch. It comes from chili peppers. The high-strength version-8% capsaicin-is sold under the brand name Qutenza® and requires a healthcare provider to apply it. Why? Because first, it burns.

When you apply it, capsaicin activates TRPV1 receptors on pain nerves. This floods the nerves with calcium and sodium, causing a burning sensation that can last 30 to 60 minutes. Then, something surprising happens: the nerves get tired. They stop sending pain signals. This is called defunctionalization. The effect lasts weeks-sometimes up to three months.

For postherpetic neuralgia, studies show an NNT of 4.4, meaning it works better than many oral drugs like pregabalin, and without drowsiness or dizziness. One patient on Reddit said it dropped their pain from 8/10 to 3/10 for eight weeks. But 30 to 50% of people quit because the initial burn is too intense.

It’s not for home use. You can’t apply it near your eyes, mouth, or genitals. And you need to wash your hands immediately after. The FDA requires special training for providers who use it. But for stubborn nerve pain that won’t respond to anything else, it’s one of the few tools that can truly change the game.

NSAID Gels: The Inflammation Fighter

NSAID gels-like diclofenac (Voltaren), ibuprofen, or ketoprofen-are the most common topical pain relievers you can buy over the counter. They’re the go-to for arthritis, sprains, and muscle strains.

They work by blocking COX enzymes in the skin and underlying tissue, which reduces prostaglandins-the chemicals that cause swelling and pain. Unlike oral NSAIDs, which can cause ulcers or raise blood pressure, topical versions deliver the drug right where it’s needed. Microdialysis studies show tissue levels can be 10 to 100 times higher than in the blood.

For knee osteoarthritis, clinical trials show about 60% of users get at least 50% pain reduction in four weeks. That’s better than placebo and close to oral NSAIDs-but with a fraction of the side effects. A 2018 Cochrane Review found topical NSAIDs have an NNT of 2.7 for acute pain, meaning less than 3 people need to use it for one to get relief. Gastrointestinal side effects? Only 0.03% with topical vs. 1.5% with oral.

But they’re not perfect. You need to apply them four times a day, at least four hours apart. Most people use too little-only about 40% apply the full 2 to 4 inch ribbon recommended. And they take time: it can take 45 minutes to feel the first effect. Also, they don’t work well for deep pain like hip arthritis. The gel only penetrates 5 to 10 mm into tissue. So if the pain is coming from inside the joint, it might not help much.

How to Use Them Right (And Avoid Common Mistakes)

Topical analgesics sound simple, but most people use them wrong. Here’s what actually works:

• Lidocaine patches: Apply to clean, dry skin. Don’t cut them. Use only one patch per area. Take them off after 12 hours. Don’t use heat-like a heating pad-on top of them.
• Capsaicin patches: Only applied by a professional. Wear gloves during application. Wash hands thoroughly. Avoid touching your face. Wait 24 hours before showering or swimming.
• NSAID gels: Use the full recommended amount-about a 2 to 4 inch ribbon. Rub it in gently until it disappears. Don’t cover with a bandage unless told to. Wait 30 minutes before washing the area. Don’t use on broken skin or rashes.

A 2019 survey of chronic pain patients found 60% of users applied too little gel. Others applied it too often, or used it on skin that was irritated. That’s why some people say it “doesn’t work”-they didn’t give it a fair shot.

Also, don’t expect instant results. Lidocaine takes 1 to 2 hours. Capsaicin’s benefit builds over days. NSAID gels need consistent use for 3 to 7 days before you see full effect. Patience matters.

Who Should Use Them-and Who Should Avoid Them

Topical analgesics are ideal for:

• Elderly patients with osteoarthritis
• People with stomach ulcers or kidney disease who can’t take oral NSAIDs
• Those on multiple medications (polypharmacy)
• Patients with localized pain-knees, elbows, lower back, or nerve pain

But they’re not for everyone:

• Don’t use capsaicin if you have sensitive skin or allergies to chili peppers.
• Avoid NSAID gels if you’ve had allergic reactions to aspirin or ibuprofen.
• Don’t use any of them on open wounds, infections, or rashes.
• The FDA warns that NSAIDs-even topical ones-may slightly increase heart attack or stroke risk in people with existing cardiovascular disease. Talk to your doctor if you have high blood pressure or heart issues.

For most people, especially those over 65, topical analgesics are one of the safest ways to manage daily pain. Medicare data shows 42% of seniors use them for arthritis-far more than younger adults.

What’s Next? The Future of Topical Pain Relief

The field is evolving fast. Researchers are testing nanoemulsion gels that deliver diclofenac deeper into tissue-2.3 times more than current versions. There’s also work on resiniferatoxin (RTX), a compound 1,000 times stronger than capsaicin, that could permanently silence pain nerves. But right now, it doesn’t absorb well through skin.

Scientists are also exploring new targets: TRPM8 channels (activated by menthol) and other receptors that could block pain without burning or numbness. These might replace opioids for mild-to-moderate pain in the next decade.

For now, the best tools are already here. And with the opioid crisis still ongoing, experts like the American Pain Society now recommend topical analgesics as a first-line treatment for localized pain-before pills, before injections.

Real People, Real Results

Reddit users and patient surveys tell the real story:

• u/KneeOA_Sufferer: “Voltaren gel takes 45 minutes to work, but gives me 6 hours of relief. No stomach pain. I’ve switched from pills completely.”
• u/ChronicPainWarrior: “The capsaicin patch was torture for 45 minutes. But after that? My PHN pain dropped from 8/10 to 3/10. Worth every second.”
• Survey respondent: “I tried everything-pills, injections, physical therapy. Only the lidocaine patch gave me consistent relief without side effects.”

But not everyone wins. About 28% report skin irritation. 35% say the gel is messy. 45% say relief is inconsistent-usually because they didn’t apply enough or didn’t wait long enough.

Success comes down to two things: using the right product for your pain type, and using it correctly. Don’t give up after one try. Try again. Follow the instructions. Talk to your pharmacist. It might be the quietest, safest solution you’ve overlooked.