Capsaicin Patch Reduces Postherpetic Neuralgia Pain & Improves Quality of Life

For individuals grappling with the persistent pain of postherpetic neuralgia (PHN), a condition arising from shingles, repeated treatments with a high-concentration capsaicin patch (HCCP) offer increasingly significant and lasting relief, according to a recent analysis of real-world patient data.

The retrospective study, published in Dermatology and Therapy, examined anonymized data from the German Pain e-Registry, encompassing 961 adults diagnosed with PHN who received at least one HCCP treatment between 2015 and 2021. Researchers followed these patients for at least 12 months, collecting patient-reported outcomes at baseline and approximately every 12 weeks, verified by physicians.

PHN is a debilitating condition characterized by chronic nerve pain in the area where shingles occurred. It affects an estimated millions of people worldwide, and can significantly impair quality of life. Current treatments often provide incomplete relief, highlighting the need for effective and well-tolerated options.

The study categorized patients based on the number of HCCP treatments received over the 12-month period: one, two, three, or four. The average age of participants was 63.8 years, with women comprising 69.7% of the cohort. Participants had experienced pain for an average of 3.3 years, and reported high baseline pain levels, with a mean 24-hour average pain intensity (API) of 61.8 on a 100-point scale.

the study demonstrated a significant decrease in mean API across all treatment groups. From a baseline of 61.8, the average pain intensity dropped to 46.8 at month 3 (P <.001) and further decreased to 31.8 at month 12 (P <.001). Notably, the most substantial reductions in pain were observed in patients receiving four HCCP treatments, with their average pain intensity falling from 63.7 at baseline to 19.6 at month 12 (P <.001).

The proportion of patients experiencing at least a 30% reduction in pain also increased with each successive treatment. At month 3, 29% of patients achieved this level of pain relief. However, by month 12, this figure rose dramatically to 99.7% among those who received four treatments, compared to just 17.6% in the group receiving only one treatment. Similarly, a 50% or greater pain reduction was reported by 92.7% of patients receiving four treatments, versus only 1.6% of those receiving a single treatment.

“Benefits were achieved following a single HCCP treatment, and repeated treatments resulted in further progressive improvements,” the researchers concluded.

Beyond pain reduction, the study revealed improvements in other aspects of patients’ well-being. Neuropathic symptoms, assessed using the 7-item painDETECT questionnaire (PDQ7), improved across multiple domains in patients receiving four treatments, particularly concerning pain attacks, numbness, and burning sensations (all P <.001). Quality of life and daily functioning also showed progressive improvements with repeated treatments. Notably, mental health scores normalized (reaching a mean score above 50) in patients receiving three or four applications, although these benefits diminished after treatment was discontinued.

Functional outcomes demonstrated early reductions in pain-related disability and sustained improvements in sleep with each successive treatment. Emotional distress and even suicidal ideation decreased significantly over the 12-month study period. Patients receiving four HCCP treatments experienced a substantial reduction in their reliance on other pain medications, decreasing from an average of 4.1 drugs at baseline to 1.4 at 12 months. Over one-third (32.7%) of this group were able to discontinue all pain medications by month 12.

The safety profile of the HCCP remained consistent with established knowledge, and discontinuation rates were generally low. This suggests that the treatment is not only effective but also reasonably well-tolerated by most patients.

It’s important to note that this study was retrospective and observational in nature, which means it cannot definitively prove a cause-and-effect relationship between HCCP treatment and pain reduction. The researchers acknowledge inherent biases associated with this type of study design. However, the large sample size and rigorous data analysis strengthen the findings and provide valuable real-world evidence supporting the efficacy of repeated HCCP treatments for PHN.

Capsaicin, the active ingredient in the patch, works by initially stimulating and then desensitizing pain receptors in the skin. As explained in a April 2020 narrative review published in the British Journal of Pain, the analgesic effects of high-dose topical capsaicin relate to the defunctionalization and retraction of nerve terminals, primarily C fibers, in the dermis and epidermis. This process can lead to a long-lasting reduction in pain signaling.

While the study provides encouraging results, it’s crucial for individuals with PHN to discuss treatment options with their healthcare provider to determine the most appropriate course of action based on their individual circumstances. The HCCP is an approved treatment option in Europe, and its availability and specific guidelines for use may vary depending on location.

Disclosure: This research was supported by Grünenthal GmbH, Germany. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.