Topical pain relief products may be growing fast in terms of use and popularity but confusion still remains about the different ingredients and their various benefits.

 

According to the recent Global Pain Index (GPI) study, commissioned by GSK (manufacturer of Voltarol), the vast majority – 93 per cent – of people in the UK experience body pain, such as arthritis, back pain, muscular aches, dysmenorrhoea and injuries, at least occasionally.

Sixty-seven per cent suffer on a weekly basis and 40 per cent experience anxiety because of their pain. The findings reflect NHS statistics, which suggest that up to 90 per cent of the population gets back pain at some point and that musculoskeletal conditions account for one in four GP consultations.

Despite the prevalence and impact of body pain in the UK, the GPI study found that just 39 per cent of sufferers are opting to manage their pain with over-the-counter analgesics. Only half said that they understood the cause of their pain, while just one in three had received a diagnosis from a healthcare professional.

“The GPI showed that body pain impacts on all aspects of life, including relationships, parenting, work and hobbies, and that many people are living in pain unnecessarily,” says Charlotte Perry, brand manager for Voltarol. “The key reasons why people don’t treat their pain are not understanding the causes of their pain, not knowing the best way to treat it, and also because of the British ‘grin and bear it’ attitude.”

Targeted relief

Half of those surveyed who do treat their body pain select traditional oral medication, yet market research suggests that more and more people are turning to topical alternatives. According to IRI data, the topical analgesics market was worth £82.9m in 2014 and experiencing healthy growth of 12.2 per cent.

Topical pain relief offers an attractive option for managing pain in many cases because the products are applied directly to the site of pain, providing targeted relief and carrying less risk of adverse effects. In addition, topicals may be more suitable for patients on complex medication regimens who wish to avoid taking more tablets or who have difficulty swallowing solid-dose forms.

“Tablets are often the go-to pain relief treatment,” says Perry, “but topicals are really driving the market at the moment. There is a lot of variety available, including gels, creams, patches and sprays and there is growing evidence that they are effective.”

Despite this growing awareness, research by The Mentholatum Company (manufacturer of Deep Relief, Deep Heat and Deep Freeze) suggests that many customers, and indeed some healthcare professionals, are still confused about the array of OTC topical pain relief options available and their different modes of action and benefits.

“Healthcare professionals are in a unique position to discuss pain relieving options, to explain the different types of product available and to highlight the fact that topical pain relief products can offer effective relief, which is applied directly to the painful area and which may help to avoid some of the unwanted gastric problems associated with long-term use of certain painkillers,” says Jillian Watt, director of marketing and new product development at Mentholatum.

“To help customers make informed choices, it is important that pharmacists and their teams are aware of the differences between each type of product, how they work, and how and when they should be used,” she adds.

Topical NSAIDs

Like their oral equivalents, topical non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and diclofenac, reduce pain by blocking the enzyme cyclo-oxygenase (COX), thereby inhibiting the production of pain-causing prostaglandins and reducing inflammation. However, while oral NSAIDs can be associated with adverse effects such as gastric irritation and urticaria, as well as certain drug interactions, topical NSAIDs are generally well tolerated.

There is a growing body of evidence in support of topical NSAID use. In 2012 a Cochrane Review concluded that “topical NSAIDs can provide good levels of pain relief without the systemic adverse events associated with oral NSAIDs when used to treat acute musculoskeletal conditions”.

Topical NSAIDs are most commonly used to relieve back pain, sporting injuries, stiff muscles, arthritic pain and rheumatism. NICE guidance published in 2014 on the care and management of osteoarthritis says healthcare professionals should consider offering topical NSAIDs to patients with OA of the hand or knee alongside core treatment, including exercise and weight loss, and ahead of oral NSAIDs, cyclo-oxygenase 2 (COX-2) inhibitors or opioids.

Heat and cold therapy

Heat therapy (thermotherapy) is thought to relieve pain by various modes of action, including increasing blood flow to the affected area, which delivers proteins and oxygen to aid healing and washes away pain-causing chemicals, relaxing stiff muscles, and blocking pain signals through a process known as ‘gate control’. The sensation of heat is thought to travel along the same pathways as pain and to shut ‘gates’ behind it so that fewer pain signals pass through.

Thermotherapy comes in the form of patches, wraps, lamps, microwavable packs and hot water bottles. A Cochrane Review found moderate evidence that heat wrap therapy reduces pain and disability for patients with back pain that lasts for less than three months, while combining heat therapy with exercise enhances the effect.

Cold therapy (cryotherapy) helps to reduce pain by constricting blood vessels, which reduces inflammation, and slows down nerve impulses, which prevents muscular spasms. It is also thought to work in a similar way to thermotherapy by overwhelming nerve endings with a cold sensation, thereby preventing pain signals from passing through nerve gates.

Cryotherapy is recommended during the early stages of acute pain and is also the most effective treatment for the itch and irritation of insect bites, according to a 2012 study in the Drug and Therapeutics Bulletin. In addition, cold therapy is a crucial step in the PRICE (Protection, Rest, Ice, Compression, Elevation) method for treating sprains and strains. Cold therapy in the form of cold compresses or ice packs should be used as soon as possible after an injury and continued for no longer than 72 hours.

After this time, and once the swelling and inflammation have subsided, heat therapy may be used. A cold compress may also provide temporary relief from the pain of shingles (herpes zoster).

 

 

Counter-irritants and rubefacients

Counter-irritants and rubefacients are believed to provide pain relief through local vasodilation or constriction and/or masking the perception of pain by overwhelming the nerve receptors with a warming or cooling sensation.

Some counter-irritants act in a similar way to cold therapy and may be effective at managing acute muscular injuries. Products containing pentane or butane evaporate at low temperatures when applied to the skin, which produces a cooling effect. Similarly, those containing levomenthol provide an analgesic effect by causing localised sensations of coldness or tingling.

Scientists recently discovered that nerve receptors that respond to cold also respond to levomenthol, which could account for this effect. Many people find that gels or rubs containing levomenthol provide effective relief for headaches and migraines, while they may also be recommended in pregnancy to help ease back pain.

Salicylate is often used in topical mouth ulcer treatments (choline salicylate), as well as in liniments as a rubefacient to soothe joint and muscle pain (methyl salicylate). It provides pain relief by producing local vasodilation and raising skin temperature, creating a warming effect similar to heat therapy.

There is limited evidence to support the use of rubefacients, however, but a systematic review published in the BMJ in 2004 did conclude that topically applied rubefacients containing salicylates might be efficacious in the treatment of acute pain. Salicylates should be avoided by people sensitive to aspirin.

Capsaicin, another rubefacient or counter-irritant, is a compound extracted from chilli peppers and used in creams and gels to treat muscular and joint pain. It works by depleting levels of a pain-inducing peptide known as substance P, which is involved in the transmission of pain signals from nerve receptors to the brain. Capsaicin cream may be prescribed for patients with localised neuropathic pain or neuralgia who wish to avoid, or who cannot tolerate, oral treatments.

Topical anaesthetics

Topical anaesthetics are applied directly to the site of pain to temporarily numb the skin by blocking nerve signals to the brain and widening the blood vessels on the surface of the skin. Topical anaesthetics such as lidocaine, lignocaine and benzocaine are used to relieve localised pain or itching on the surface of the skin caused by mouth ulcers, haemorrhoids, sunburn and insect bites or stings. They can also be applied to the skin before vaccination to numb the area.

Topical anaesthetics should only be used for one to two weeks and may cause mild skin reactions, such as redness, itching or swelling, although this is usually short-lived.

Electrical stimulation

A popular alternative topical pain relief method is transcutaneous electrical nerve stimulation (TENS). TENS machines are electrical devices designed to help manage chronic back pain, arthritis and muscular pain, and to provide a drug-free method of pain relief during childbirth.

They act by delivering a tiny, painless electrical pulse via electrodes attached to the skin to key points along a nerve pathway. TENS machines are based on the gate control theory of pain and act by closing nerve gates in the spinal cord by boosting the production of endorphins and blocking pain impulses. There is little evidence to date to support the use of TENS machines, although they may be effective in certain individuals.

Herbal remedies

Various topical pain relief preparations contain herbal ingredients, which present an option to people who wish to avoid drug treatments. For example, arnica is a licensed homeopathic remedy and traditional herbal medicine that has anti-inflammatory properties. It may help to relieve muscular aches and pains, stiffness, sprains, bruises and swelling after contusions.

Another popular herbal medicine with pain-relieving properties is Devil’s Claw. Gels containing an extract of the plant root may relieve muscular aches, rheumatism and joint pain. Research suggests that Devil’s Claw extracts can block several pathways that cause joint inflammation.

Witch hazel, which is obtained from the leaves and bark of the North American witch hazel shrub, is an astringent that draws tissues together and constricts blood vessels. When applied to the skin, witch hazel gels or liquids may relieve itchy skin problems such as insect bites and haemorrhoids.

Drug-free option

A relatively new OTC option for managing pain associated with osteoarthritis is a drug-free gel containing microscopic spheres known as sequessome vesicles. These spheres are made up of phospholipids, which occur naturally in the body and contribute towards the lubrication effect of synovial fluid.

When the gel is applied to OA-affected joints, the sequessome vesicles are said to penetrate the skin and seek out the synovial fluid, coating the cartilage and lubricating the joint. According to Pro Bono Bio, there have been five clinical studies that have demonstrated reductions in pain of around 50 per cent and improvements in physical function of around 40 per cent.

 

 There is a growing body of evidence in support of topical NSAID use