A critical review of the capsaicin 8% patch for the treatment of neuropathic pain associated with diabetic peripheral neuropathy of the feet in adults

ABSTRACT

Introduction

Diabetes is an increasingly prevalent disorder affecting nearly 1-in-5 adults, of which half will experience diabetic peripheral neuropathy (DPN) and a quarter will suffer from diabetic peripheral nerve pain (DPNP), severely impacting quality of life. The currently approved treatment options are typically centrally acting agents whose use is limited by systemic effects and drug interactions. The capsaicin 8% dermal patch was recently approved by the U.S. FDA for the treatment of DPNP.

Areas covered

The authors review the available literature regarding the use of high-concentration capsaicin 8% patch for the treatment of diabetic peripheral neuropathy and neuropathic pain and discuss implementing its use in clinical practice.

Expert opinion

The high-concentration capsaicin 8% patch is an effective and well-tolerated treatment option for treating DPNP. Capsaicin 8% patch may be used alone or in combination with other oral therapies and can provide rapid and sustained neuropathic pain relief following a single application and is safe and effective when used long term.

KEYWORDS:

• Capsaicin
• neuropathic pain
• diabetic neuropathy
• distal symmetric polyneuropathy

Article highlights

• Diabetes is an increasingly prevalent disorder and affects more than 18% of the adult population over the age of 18 and more than 25% of adults over 65 in the United States.

• By 2040, as many as 600 million adults worldwide may be affected by diabetes.

• Diabetic neuropathy occurs in about 50% of individuals living with diabetes, and about 25% will experience neuropathic pain. This pain typically follows the pattern of a distal symmetric polyneuropathy and is most severe in the toes, feet, and legs.

• Patients with painful diabetic neuropathy may report burning, tingling, pins-and-needles, pricking, electric-shock, or deep aching sensations in the lower extremities, which may have a nocturnal predominance.

• Despite the availability of several classes of oral medications including anticonvulsants (e.g. gabapentin, pregabalin), antidepressants (e.g. duloxetine, amitriptyline), and opioids, painful diabetic neuropathy is often poorly controlled and remains a major source of morbidity for patients and a challenge for physicians managing this condition.

• Capsaicin is a potent and selective transient receptor potential vanilloid-1 (TRPV-1) agonist which is found on C-fiber and Aδ neurons. Prolonged capsaicin exposure leads to ‘defunctionalization’ of afferent pain-transmitting sensory nerve fibers and secondarily mediates central pain sensitization pathways.

• The high-concentration capsaicin 8% patch (Qutenza) was approved by the U.S. FDA in 2009 for post-herpetic neuralgia and in 2020 for neuropathic pain associated with diabetic peripheral neuropathy. In Europe, the capsaicin 8% patch has been approved for the treatment of peripheral neuropathic pain of all etiologies.

• Capsaicin 8% patches may be used alone or in combination with other oral therapies including traditional first-line options such as anticonvulsants (e.g. gabapentin, pregabalin) or antidepressants (e.g. duloxetine, amitriptyline).

• Each single 30-min application of up to four capsaicin 8% patches can provide rapid onset and sustained pain relief for up to 12-weeks from DPNP.

• Repeat application of the capsaicin 8% patch every 12-weeks as necessary is safe and effective in patches with diabetes who were followed for 52-weeks.

• Capsaicin 8% patches are generally well tolerated. The most common adverse reactions are those of localized application site pain, burning, erythema, and pruritis. These symptoms may occur at the time of patch application, and typically resolve rapidly over the first several days following the application. Pre-treatment with topical analgesic medications may preempt this discomfort. Local cooling methods including ice or ice packs, and additional analgesic medication may ameliorate post-procedural symptoms.

• Systemic side effects are minimal with the most commonly reported adverse effect being transient hypertension occurring in about 3% of recipients thought to be attributable to discomfort from patch application.

• Qutenza is mainly metabolized into inactive metabolites by liver enzymes, however, dose adjustments are not considered necessary in patients with renal or hepatic dysfunction, nor in geriatric patients.

Declarations of interests

DM Simpson receives consulting fees from Averitas/Grunenthal. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or conflict with the subject matter or materials discussed in this manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.