The use of a SINGLE application of a 8% (vs 0.025 – 0.075 usually used) capsaicin patch (NGX-4010) resulted in significant relief for over 12 weeks in HIV neuropathic pain. Given the old technique (4 X/day gel application for two weeks just to see any benefit) was messy and labor intensive, this new approach could be a godsend.
Neurology. 2008 Jun 10;70(24):2305-13.
Controlled trial of high-concentration capsaicin patch for treatment of painful HIV neuropathy. Simpson DM, Brown S, Tobias J; NGX-4010 C107 Study Group.
Like the complaints on drug results for Radiculopathy pain previously described in Entanercept blog report, they mention that HIV neuropathy does not do well with many meds:
“Studies of restorative treatments for HIV-DSP have yielded disappointing results. Although the primary management approach remains pain reduction, clinical trials evaluating amitriptyline, mexiletine, acupuncture, memantine, topical lidocaine gel, lamotrigine, gabapentin, and opioids have yielded negative, inconsistent, or poorly generalizable results.Cannabinoids may have a role in the treatment of painful HIV-DSP.”
Hence the push to new treatments:
1) Area pretreated with 4% lidocaine cream (Ferndale labs, MI) for 60 minutes. (Could make your own with 4% lidocaine hydrochloride in Lipoderm cream)
2) 8% (w/w) capsaicin patches (each 14 X 20 cm size) added (up to 4 of them) to cover max of 22″ X 31″ size
3) Patches left on 30, 60, 90 minutes depending on arm of study
4) “Oxycodone hydrochloride oral solution (1 mg/mL) or equivalent could be administered at the onset of treatment-associated discomfort and as required. Patients could take hydrocodone bitartrate/acetaminophen 5 mg/500 mg for up to 7 days.”
Results: “No dose response was apparent. Pain decrease from baseline during weeks 2 to 12 for the NGX-4010 30-, 60-, and 90-minute groups were 27.7%, 15.8%, and 24.7% (p = 0.0007, 0.287, and 0.0046 vs control); 42%, 24%, and 36% of NGX-4010 subjects in the 30-, 60-, and 90-minute groups had a >=30% mean reduction in pain (p = 0.0015, p = 0.39, and p = 0.0092 vs control).”
Local skin irritation (use 0.5% hydrocorticone cream) and pain were mild side effects.
Comment – wow that could prove useful potentially for a variety of neuropathies where the skin is intact.
This is not the first time time concentration capsaicin has been shown to have prolonged effects.
I wonder if the capsaicin could be impregnated in a thin layer of gelatin and that used for application. One would have to be VERY careful not to get it in the eye – the 1/15th strength gel can cause major pepper spray eye effects – I wonder if 8% could cause permanent eye damage. Gloves would always be needed.