Topical Therapies in the Management of Chronic Pain

Abstract

Chronic pain, whether localized or generalized, is a widespread, often debilitating condition affecting > 25% of adults in the United States. Oral agents are the cornerstone of chronic pain treatment, but their use may be limited in certain patients, particularly the elderly. Topical therapies offer advantages over systemically administered medications, including the requirement of a lower total systemic daily dose for patients to achieve pain relief, site-specific drug delivery, and avoidance of first-pass metabolism, major drug interactions, infections, and systemic side effects. Several types of topical agents have been shown to be useful in the treatment of patients with chronic pain. Both capsaicin and topical diclofenac have been shown to be effective in the treatment of patients with chronic soft-tissue pain. In patients with hand and knee osteoarthritis (OA), the American College of Rheumatology generally recommends oral treatments (acetaminophen, oral nonsteroidal anti-inflammatory drugs [NSAIDs], tramadol, and intra-articular corticosteroids) and topical NSAIDs equally, favoring topical agents only for patients who have pre-existing gastrointestinal risk or are aged ≥ 75 years. Topical NSAIDs have been shown to provide relief superior to that of placebo and comparable to that of oral ibuprofen. Similarly, ketoprofen gel has been shown to be superior to placebo and similar to oral celecoxib in reducing pain in patients with knee OA. Different formulations of topical diclofenac (including the diclofenac hydroxyethyl pyrrolidine patch, diclofenac sodium gel, and diclofenac sodium topical solution 1.5% w/w with dimethyl sulfoxide USP) have been shown to be superior to placebo and comparable to oral diclofenac in the treatment of patients with pain due to knee OA, with a lower incidence of gastrointestinal complaints than with the oral formulation. In patients with neuropathic pain, topical forms of both capsaicin and lidocaine have been shown to be useful in the treatment of postherpetic neuralgia and diabetic peripheral neuropathic pain. Lidocaine has also demonstrated efficacy in relieving patient pain due to complex regional pain syndrome and may be useful in the treatment of patients with neuropathic pain who have cancer, although clinical trial results have not been consistent. Data suggest that topical therapies may offer a safe, well-tolerated, and effective alternative to systemic therapies in the treatment of patients with chronic, localized musculoskeletal and neuropathic pain.

Rethinking chronic pain in a primary care setting

“…[117] Other treatments for chronic pain Though oral agents are the cornerstone of pharmacologic therapy for chronic pain their use may be limited in certain patients, particularly the elderly. [118] Topical therapies have shown efficacy against chronic pain and offer several advantages over systemic medications including the requirement for a lower total systemic daily dose, site-specific drug delivery, the potential to avoid first-pass metabolism, and fewer major drug interactions and systemic side effects. [118][119][120] Nonselective NSAIDs, for example, have been formulated as patches and topical gel solutions for the treatment of predominantly nociceptive pain conditions such as OA, whereas lidocaine and capsaicin have been formulated as patches for the treatment of predominantly neuropathic pain conditions such as pDPN.…”

Evaluation of a root extract gel from <i>Urtica dioica</i> (Urticaceae) as analgesic and anti-inflammatory therapy in rheumatoid arthritis in mice

“…The conventionally used NSAIDs in RA have also been developed into topical or transdermal forms for various benefits, including reduced adverse effects, reduced drug dosage, improved patient compliance, and prolonged drug release [6,8,20]. Herbal drugs have long been used in traditional medicine for various conditions of pain and inflammation including arthritis.…”

“…However, oral NSAIDs are often needed at high dosing frequencies and show side effects, such as gastric irritation and moderate plasma level fluctuations, which may lead to the chance of an overdose. Thus, to overcome these limitations and to improve bioavailability, prolong the effects, and minimize side effects, topical or transdermal delivery has been investigated for various NSAIDs [6][7][8].…”

Effectiveness of lidocaine patches for pain treatment after total knee arthroplasty

“…[16][17] Topical lidocaine therapy does not extinguish the trigger, namely the surgical trauma, but prevents the spread of the pain stimulus. 10,18 Because lidocaine is a local anesthetic, the amount absorbed in the topical modality under study is negligible, 10,19,20 producing local analgesia without reaching MedicalExpress (Sao Paulo, online) 2017 December;4(6):M170603 Lidocaine for pain after total knee arthroplasty Sadigursky D the sensory blockade level. 9,10 This is known as "target peripheral analgesia", 10 which is ideal for recovery after the surgical procedure.…”