Getting on Top of Pain: Topical NSAIDs

Tennis - Sloane Stephens of the U.S. in action during her first-round match against Clara Burel of France. REUTERS/Shannon Stapleton

Musculoskeletal conditions affecting bones, joints, and muscles are the leading causes of global disability, impacting approximately 1.71 billion⁽¹⁾. Common issues include low back pain, OA, rheumatoid arthritis (RA), gout, and lupus. The prevalence of musculoskeletal pain in adults ranges from 18% to 80%, exacerbated by factors like population growth, urbanization, and increased life expectancy⁽²⁾. Clinicians commonly use non-steroidal anti-inflammatory drugs (NSAIDs) for pain management, but they can cause gastrointestinal, cardiovascular, and renal issues when taken orally. In the USA, 65.4% of osteoarthritis (OA) patients and 56.1% of chronic low back pain patients use NSAIDs, while the UK saw 10.36 million prescriptions for oral NSAIDs in 2020⁽³⁾. Topical NSAIDs are becoming increasingly popular, particularly among high-risk patients, as they provide localized pain relief with minimal systemic exposure⁽⁴⁾.

Burden of Disease

Painful musculoskeletal conditions, such as low back pain and OA, are common worldwide. These conditions may be age-related, affecting more than half of adults over 60 and rare in children. In the US, the 2009 National Health Interview Survey found that 28% of people reported lower back pain, 19% knee pain, 15% neck pain, and 8% hand pain over three months. A 2020 cross-sectional survey of over 52,000 individuals across 14 countries revealed that half experienced significant pain impacting their lives⁽⁵⁾.

The Global Burden of Disease Project measures health loss using disability-adjusted life years (DALYs) and years lived with disability (YLDs). The 2010 survey first highlighted musculoskeletal pain as a leading cause of global disability. By 2016, low back and neck pain ranked third in total DALYs, behind only ischemic heart disease and cerebrovascular disease. In 2017, musculoskeletal conditions accounted for 18% of all YLDs globally, with a 19.9% increase in YLDs from 2000 to 2017. Musculoskeletal pain significantly affects emotional wellbeing in 40% and quality of life in 59% of individuals. All this emphasizes the critical need for effective pain management strategies that minimize the risk of adverse side effects⁽⁶⁾.

Mechanism of Action

Topical NSAIDs penetrate the skin, reaching the underlying tissues and joints. They inhibit cyclooxygenase (COX) enzymes, reducing prostaglandin production and subsequent pain and inflammation. This localized action minimizes systemic absorption, reducing the risk of adverse effects.

Benefits

1. Improved safety profile: Topical NSAIDs are associated with a lower risk of gastrointestinal bleeding, cardiovascular events, and renal impairment compared to oral NSAIDs. Reducing systemic exposure minimizes the risk of adverse effects, making them suitable for patients with comorbidities or those taking multiple medications.
2. Targeted pain relief: Direct application to the affected area provides rapid and effective pain relief, reducing the need for systemic therapy.
3. Convenience: Topical NSAIDs are easy to apply, and there is a reduced need for frequent dosing⁽⁷⁾.

Evidence-Based Uses

1. Osteoarthritis: Topical NSAIDs effectively reduce pain and improve function in knee, hip, and hand OA patients.
2. Acute musculoskeletal injuries: Topical NSAIDs can provide rapid pain relief and reduce inflammation in acute injuries, such as sprains and strains.
3. Postoperative pain: Clinicians can prescribe them in conjunction with oral analgesics to reduce the need for opioids and minimize the risk of adverse effects.
4. Chronic pain: Clinicians can use them as part of a multimodal pain management strategy for chronic conditions, such as fibromyalgia and neuropathic pain⁽⁷⁾.

Risks and Contraindications

As with any medication, Topical NSAIDs carry risks and contraindications. These include skin irritation, such as redness, itching, and burning. Furthermore, they can elicit allergic reactions and, in rare cases, lead to dermatitis. Finally, clinicians must be cautious when working with patients with a history of hypersensitivity to NSAIDs, asthma, or aspirin exacerbated respiratory disease (AERD) (or Samster’s Triad)(see figure 1)⁽⁸⁾.

Aspirin exacerbated respiratory disease is characterized by three primary components: bronchial asthma, nasal polyps, and aspirin intolerance. The pathogenesis is linked to a nonallergic hypersensitivity reaction, particularly an abnormal metabolism of arachidonic acid, leading to an imbalance in the synthesis of eicosanoids such as prostaglandins and leukotrienes. This causes inflammation in the respiratory tract. Clinically, it often begins with nasal symptoms and progresses to asthma and aspirin intolerance over time. Diagnosis typically involves aspirin provocation tests, and management may include aspirin desensitization, especially for patients with recurrent nasal polyps and overdependence on corticosteroids. In addition, patients with AERD may develop life-threatening symptoms, including an asthmatic attack or a special rash, when they take aspirin or nonsteroidal anti-inflammatory medications⁽⁸⁾.