Pilot Study of High-Dose Capsaicin Patches to Treat Postherpetic Neuralgia Pain

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).