Introduction: Capsaicin 179 mg (8% weight per weight) cutaneous patch ("capsaicin patch") is a recommended topical treatment for peripheral neuropathic pain (PNP). In older patients, topical treatments may be preferred over systemic treatments, but data specific to the older population are scarce. Methods: We conducted pooled analyses of multiple clinical trials to evaluate efficacy and safety of capsaicin patch in older patients. The analysis of efficacy included four randomized, double-blind, 12-week studies with similar trial design comparing a single treatment of capsaicin 179 mg cutaneous patch vs low-dose control patch in post-herpetic neuralgia. For the safety evaluation, data were pooled from 18 interventional studies in which capsaicin patch was used in PNP with varying etiologies. Results: Capsaicin patch had similar analgesic efficacy in elderly (n=582) and non-elderly patients (n=545) in terms of change from baseline to 2-12 weeks in the 11-point numeric pain rating scale (NPRS) score for average pain over the previous 24 hours. In both age groups, decrease in NPRS score was significantly greater with capsaicin patch vs control. Older patients treated with capsaicin patch were significantly more likely than those in the control group to achieve responder status (ie mean decrease in NPRS score from baseline to week 2-12 of at least 30% or >= 2 points): 36.1% vs 27.1% (odds ratio [OR] [95% CI] 1.52 [1.06, 2.18]; P=0.0231) and 33.1% vs 20.9% (OR [95% CI] 1.90 [1.30, 2.78]; P=0.0009) for active treatment vs control group, respectively. Similar proportions of non-elderly patients (n=2,311) and elderly patients (n=537) treated with capsaicin patch experienced treatment-emergent adverse events (TEAEs) (81.6% and 78.1%, respectively) and serious TEAEs (8.2% and 7.2%), with application -site reactions the most common TEAEs in both groups. Conclusion: The capsaicin patch was equally efficacious and well tolerated in older patients as in younger patients. Plain language summary: Peripheral neuropathic pain is a common challenge among the elderly, yet effective treatments for this age group remain underexplored. This research focuses on the use of a high-concentration capsaicin patch, a specialized treatment for this type of pain. The patch, which is applied directly to the affected skin area, has been shown to reduce pain significantly for up to 12 weeks. This analysis of multiple clinical trials showed that the high-concentration capsaicin patch significantly reduced pain intensity and was well tolerated in older patients with peripheral neuropathic pain.

Introduction: Despite their poor tolerance, especially in the elderly, weak opioids (WO) remain commonly prescribed for patients with knee osteoarthritis (KOA). We compared the efficacy and safety of a new wearable transcutaneous electrical nerve stimulation (W-TENS) device with WO for the treatment of moderate-to-severe, nociceptive KOA chronic pain. Methods: The study was a non-inferiority, multicentric, prospective, randomized, single-blind, controlled, 2-parallel groups Trial. A total of 110 patients with KOA were included (Kellgren-Lawrence radiographic grade ⩾2; American College of Rheumatology criteria), with chronic moderate-to-severe nociceptive pain (mean 8-day pain intensity (PI) ⩾ 4 on an 11-point numerical rating scale), in failure to non-opioid analgesics, including nonsteroidal anti-inflammatory drugs (NSAIDs). Patients with neuropathic pain were excluded. The co-primary endpoints were mean PI at 3 months (M3) and number of potentially treatment-related adverse events (TRAEs). Secondary outcomes included Western Ontario MAC Master University function subscale (range, 0–68), additional pain and quality of life measures, and responder rates. Results: The non-inferiority of W-TENS was demonstrated in both the per protocol (PP) and intent-to-treat (ITT) populations. At M3, PI in PP population was 3.87 (2.12) compared with 4.66 (2.37) [delta: −0.79 (0.44); 95% CI (−1.65, 0.08)] in W-TENS and WO groups, respectively. A planned superiority analysis showed a significant superiority of W-TENS over WO on PI at M3 (p = 0.0124). The number of TRAEs was significantly lower in the W-TENS group (n = 7) than in the WO group (n = 36) (p < 0.001). Other secondary outcomes also favored W-TENS. Conclusion: W-TENS was more effective and better tolerated than WO in the treatment of chronic nociceptive KOA pain and offers an interesting non-pharmacological analgesic alternative in the management of KOA. Trial Registration: ClinicalTrials.gov: NCT03902340

Localized neuropathic pain symptoms are reported after knee surgery in 30% to 50% of patients. 5% lidocaine plaster (LP5) is recommended for localized neuropathic pain, but evidence in postsurgery neuropathic pain is missing. This study focuses on the effectiveness of LP5 on allodynia, hyperalgesia, and thermal stimuli in postsurgery knee localized neuropathic pain. A randomized double-blind, 2 parallel groups, controlled trial (NCT02763592) took place in 36 patients (age, 69.4 ± 7.3 years) at the Clinical Pharmacology Center, University Hospital Clermont-Ferrand, France. Patients randomly received LP5 or placebo plaster during 3 months. Neuropathic pain intensity and several parameters (dynamic mechanical allodynia, mechanical [von Frey], heat and cold detection and pain thresholds [Pathway Medoc], and size of the allodynic area were recorded at each visit [inclusion, day 7, 15, month 1, 2, and 3]). From day 7 onwards, dynamic mechanical allodynia diminished progressively of ≥ 30% over 3 months ( P = 0.003) in 96% of patients (23/24) and of ≥ 50% in 83% of patients (20/24). Cold pain and maximal mechanical pain thresholds improved over 3 months ( P = 0.001 and P = 0.007, respectively). This study shows for the first time the effectiveness of LP5 on dynamic mechanical allodynia, pain, pressure, and cold thresholds over 3 months in knee localized neuropathic pain. Beyond the inhibition of sodium channels by LP5, these findings suggest the involvement of cold and mechanical receptors that participate to pain chronicisation and also of the non-negligible placebo effect of the patch, items that need to be explored further and challenged in other etiologies of localized neuropathic pain.