pilot study of high-dose capsaicin patches to treat postherpetic neuralgia pain

Conditions: Neuralgia; Pain; Peripheral Nervous System Diseases; Herpes Zoster

Summary: the purpose of this study is to gain initial information on the tolerability of high-dose capsaicin patches in patients with painful postherpetic neuralgia. the study will also collect preliminary information on safety and efficacy.


Eligibility criteria:
eligibility criteria inclusion criteria: patients may be eligible for this study if they: * have a diagnosis of painful postherpetic neuralgia and are at least 6 months post vesicle crusting. * are in good health. * have an adequate pain score during the screening period. * have painful areas (maximum of two sites) below the neck. * if female, are of non-childbearing ability as defined by absence of menses for a minimum of 3 months or surgically sterile. * if male, are willing to agree to take adequate birth control precautions with their partner for 60 days following experimental drug exposure. * have unbroken skin with good perfusion over the painful area(s). * have the ability to feel capsaicin-mediated sensations, as evidenced by ability to feel topically applied otc capsaicin cream. * are on a stable and continuous medication regimen, with no change in dosage for 21 days prior to study start, and are willing to maintain concomitant medications at current doses throughout the study. * are willing and able to use oral opioid-based analgesic agents for relief, in case this is needed to relieve acute pain associated with the application of capsaicin patches. * are 18 years of age or older. * are willing and able to comply with the protocol exclusion criteria: patients will not be eligible for this study if they: * have diffusely distributed neuropathic pain (i.e., pain that is evident in more than 2 different sites). subjects must not have significant pain outside the areas to be treated. * have any implanted medical device (spinal cord stimulator, intrathecal pump or peripheral nerve stimulator) for the treatment of neuropathic pain. * currently (within the past 21 days) use topically applied non-steroidal anti-inflammatory drugs, local anesthetics, steroids or capsaicin products on the painful areas. * currently (within the past 21 days) use topical agents such as lidoderm patch 5%, topical steroids or aspirin. * have a history or current problem with prescription drug or illicit substance abuse (from self report or as judged by investigator). * currently have an abuse problem with alcohol (from self-report or as judged by investigator). * are suspected of psychosocial gain/benefit of continued pain as judged by the investigator or primary treating physician. * plan to travel more than 100 miles from home during the study or engage in unusual activities that might exacerbate pain. * have poor cardiac, renal, hepatic, or pulmonary function judged by the investigator or primary treating physician. * have a laboratory value at screening outside the normal range, unless it is judged by the investigator as not clinically significant after appropriate evaluation. * have hypersensitivity to capsaicin (i.e., chili peppers or otc capsaicin products), local anesthetics, oral opioid-based analgesic agents, or adhesives. * have a high tolerance to opioids. * currently using class 1 anti-arrhythmic drugs (such as tocainide and mexiletine).

Keywords: analgesics/*therapeutic use capsaicin/*administration & dosage/adverse effects herpes zoster/*complications/drug therapy neuralgia/*drug therapy/etiology pain capsicum pepper dermal assessment pain measurement diary phn postherpetic neuralgia allodynia hyperalgesia shingles varicella