Topical pain relievers

Topical pain relievers are medicines you put on the skin over a painful area. They come as creams, gels, sprays, roll-ons and patches. Many are sold over the counter, and some stronger versions need a prescription.

The main types are:

• Topical NSAIDs. Anti-inflammatory medicine from the same family as ibuprofen, in a gel, liquid or patch. Diclofenac gel (Voltaren) is the only one sold over the counter in the US; the others need a prescription.
• Cooling and warming rubs. Also called counterirritants, these contain menthol, camphor or methyl salicylate (oil of wintergreen), alone or together.
• Capsaicin. The substance that makes chili peppers hot. Low-strength creams and patches are sold over the counter, and a much stronger patch is applied in a clinic by prescription.
• Lidocaine. A numbing medicine. Creams and patches are sold over the counter, and stronger patches, such as Lidoderm, need a prescription.
• Compounded creams. Creams a pharmacy mixes to order, often combining several medicines.

People use topicals for back and neck pain, but most of the research is on other problems, such as sprains, strains, and knee or hand arthritis.

• Topical NSAIDs soak through the skin into the tissue underneath and calm inflammation there. Much less medicine reaches the bloodstream than with pills.
• Counterirritants create a cooling or warming feeling that competes with pain signals. Menthol, for example, switches on the nerve sensors that detect cold.
• Capsaicin first causes burning or stinging. With repeated use, the pain-sensing nerve endings in that area of skin become less sensitive.
• Lidocaine quiets pain signals from nerve endings in the skin, usually without fully numbing it.

Part of the relief seems to come from applying a product at all. In arthritis studies, people using a placebo gel improved more often than people taking placebo pills.

Before you start

Check the active ingredients, since many products combine more than one, such as menthol with lidocaine. Tell your clinician or pharmacist if you are pregnant or breastfeeding, take a blood thinner, are allergic to aspirin or other pain relievers, already take an NSAID by mouth, or have kidney disease, heart disease, high blood pressure, asthma, or a past stomach ulcer or bleeding.

Using it

Put it only on clean, unbroken skin, never on cuts, rashes or irritated skin. Never use a heating pad, hot water bottle or heat lamp over a rub or patch, and do not wrap the area tightly. Heat and tight wraps raise the risk of burns.

Wash your hands after applying, unless you are treating your hands, and keep the product away from your eyes and mouth. This matters most with capsaicin.

Capsaicin often burns or stings at first. For many people this eases with regular use, but some stop using it because of the burning. The high-strength capsaicin patch is applied by a trained clinician, often after a numbing medicine, because it can cause intense burning.

Patches are worn for a set time and then removed. Follow the label or your prescriber. Using more patches or cream than the label says, leaving a patch on longer than directed, or putting it on broken skin can let too much medicine into the blood. Store all of these products where children cannot reach them.

Giving it time

In studies of sprains and strains, benefit was usually judged after about a week. If a product has not helped by then, ask your clinician or pharmacist about other options.

For sprains, strains and similar injuries, some topical NSAID gels and patches work well in studies, probably about as well as NSAID pills. The diclofenac gel sold over the counter in the US is labeled only for arthritis pain. For knee and hand arthritis, they help a smaller share of people over several weeks.

For back pain, there is little direct research on topical NSAIDs. In one trial of people seen in an emergency room for new low back pain, diclofenac gel helped less than ibuprofen pills, and adding the gel to the pills added no benefit. [21]

Creams and patches made from capsicum (cayenne pepper) probably ease long-lasting low back pain more than a placebo, based on a few moderate-quality trials. It is unclear whether they help new low back pain. [13]

For rubs with methyl salicylate, the evidence is weak. Older, smaller studies suggested a benefit, but larger, newer studies found none. Menthol rubs have been studied very little for back or neck pain.

Evidence for lidocaine patches in back pain is weak. A review found no strong randomized trials, only studies without a comparison group. The prescription lidocaine patch and the high-strength capsaicin patch are approved for certain nerve pain, such as pain after shingles, and over-the-counter diclofenac gel is labeled for arthritis pain (opens in a new tab) in joints such as the knees and hands. None of these three is labeled for back or neck pain.

In a large trial, compounded pain creams worked no better than a placebo cream, and they cost more. A major research review of topical pain relievers included no studies on neck pain, so the low-back results are the best guide we have. [1] [16]

Because little medicine reaches the blood, topicals cause fewer whole-body side effects than pills. Skin problems are the most common downside, and a few risks are serious.

Common and mild

• Redness, itching or a rash where the product was applied.
• Burning or stinging with capsaicin, which is common.

Less common

• Allergic skin reactions to an ingredient, such as methyl salicylate or lidocaine.
• Methyl salicylate is related to aspirin and passes through the skin. Heavy use has made the blood thinner warfarin work too strongly and caused bleeding.
• Topical NSAIDs carry the same label warnings as NSAID pills (opens in a new tab), such as stomach bleeding and heart risks, even though these problems are much less likely with a gel.
• A topical NSAID adds to any NSAID you take by mouth, so check with your clinician before using both.

Rare but serious

• Chemical burns. In 2012 the US Food and Drug Administration warned (opens in a new tab) that over-the-counter muscle and joint rubs and patches with menthol, methyl salicylate or capsaicin had caused rare but serious burns, some after one use.
• Most of the severe burns involved stronger menthol or methyl salicylate products. People with numb skin, for example from diabetes, may not feel a burn starting.
• Poisoning if swallowed. Products with methyl salicylate or camphor can seriously harm a child, even in small amounts.

Other downsides

• Prescription and compounded products can be expensive.

Wash off the product and call your clinician if you feel real pain or severe burning, or see blisters or swelling where you applied it. Get emergency care for hives, swelling of the face or lips, or trouble breathing. If a child swallows a product, call Poison Control at 1-800-222-1222 right away.