NGX-4010, a capsaicin 8% dermal patch, administered alone or in combination with systemic neuropathic pain medications, reduces pain in patients with postherpetic neuralgia.
ABSTRACT Analyses of integrated data from 4 controlled postherpetic neuralgia studies evaluated the effect of NGX-4010, a capsaicin 8% patch, administered alone or together with systemic neuropathic pain medications.
Patients recorded their “average pain for the past 24 hours” daily for 12 weeks using an 11-point Numeric Pain Rating Scale (NPRS). Efficacy assessment included the percentage NPRS score reduction from baseline during weeks 2 to 8 and 2 to 12, the proportion of patients responding during weeks 2 to 8 and 2 to 12 and the Patient Global Impression of Change (PGIC) at weeks 8 and 12.
During the studies, 302 NGX-4010 and 250 control (capsaicin, 0.04% wt/wt) patients were using at least 1 systemic neuropathic pain medication; 295 NGX-4010 and 280 control patients were not. During weeks 2 to 8, NGX-4010 patients reported greater reductions in NPRS scores compared with control both in patients using systemic neuropathic pain medications (26.1% vs. 18.1%, P=0.0011) and in patients not using these medications (36.5% vs. 26.2%, P=0.0002). Patients not using systemic neuropathic pain medications reported a greater reduction in pain compared with patients using these medications in both, NGX-4010 and control groups, resulting in comparable treatment differences between NGX-4010 and control regardless of systemic neuropathic pain medication use. Similar results were seen during weeks 2 to 12, for the responder and PGIC analyses. Transient, capsaicin-related application site reactions were the most common adverse events and not affected by systemic neuropathic pain medication use.
A single 60-minute NGX-4010 treatment reduces PHN for up to 12 weeks regardless of concomitant systemic neuropathic pain medication use.
- SourceAvailable from: link.springer.com[show abstract] [hide abstract]
ABSTRACT: Postherpetic neuralgia (PHN) represents a potentially debilitating and often undertreated form of neuropathic pain that disproportionately affects vulnerable populations, including the elderly and the immunocompromised. Varicella zoster infection is almost universally prevalent, making prevention of acute herpes zoster (AHZ) infection and prompt diagnosis and aggressive management of PHN of critical importance. Despite the recent development of a herpes zoster vaccine, prevention of AHZ is not yet widespread or discussed in PHN treatment guidelines. Diagnosis of PHN requires consideration of recognized PHN signs and known risk factors, including advanced age, severe prodromal pain, severe rash, and AHZ location on the trigeminal dermatomes or brachial plexus. PHN pain is typically localized, unilateral and chronic, but may be constant, intermittent, spontaneous and/or evoked. PHN is likely to interfere with sleep and daily activities. First-line therapies for PHN include tricyclic antidepressants, gabapentin and pregabalin, and the lidocaine 5 % patch. Second-line therapies include strong and weak opioids and topical capsaicin cream or 8 % patch. Tricyclic antidepressants, gabapentinoids and strong opioids are effective but are also associated with systemic adverse events that may limit their use in many patients, most notably those with significant medical comorbidities or advanced age. Of the topical therapies, the topical lidocaine 5 % patch has proven more effective than capsaicin cream or 8 % patch and has a more rapid onset of action than the other first-line therapies or capsaicin. Given the low systemic drug exposure, adverse events with topical therapies are generally limited to application-site reactions, which are typically mild and transient with lidocaine 5 % patch, but may involve treatment-limiting discomfort with capsaicin cream or 8 % patch. Based on available clinical data, clinicians should consider administering the herpes zoster vaccine to all patients aged 60 years and older. Clinicians treating patients with PHN may consider a trial of lidocaine 5 % patch monotherapy before resorting to a systemic therapy, or alternatively, may consider administering the lidocaine 5 % patch in combination with a tricyclic antidepressant or a gabapentinoid to provide more rapid analgesic response and lower the dose requirement of systemic therapies.Drugs & Aging 10/2012; · 2.65 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: A large number of pharmacological studies have used capsaicin as a tool to activate many physiological systems, with an emphasis on pain research but also including functions such as the cardiovascular system, the respiratory system, and the urinary tract. Understanding the actions of capsaicin led to the discovery its receptor, transient receptor potential (TRP) vanilloid subfamily member 1 (TRPV1), part of the superfamily of TRP receptors, sensing external events. This receptor is found on key fine sensory afferents, and so the use of capsaicin to selectively activate pain afferents has been exploited in animal studies, human psychophysics, and imaging studies. Its effects depend on the dose and route of administration and may include sensitization, desensitization, withdrawal of afferent nerve terminals, or even overt death of afferent fibers. The ability of capsaicin to generate central hypersensitivity has been valuable in understanding the consequences and mechanisms behind enhanced central processing of pain. In addition, capsaicin has been used as a therapeutic agent when applied topically, and antagonists of the TRPV1 receptor have been developed. Overall, the numerous uses for capsaicin are clear; hence, the rationale of this review is to bring together and discuss the different types of studies that exploit these actions to shed light upon capsaicin working both as a tool to understand pain but also as a treatment for chronic pain. This review will discuss the various actions of capsaicin and how it lends itself to these different purposes.Pharmacological reviews 10/2012; 64(4):939-71. · 17.00 Impact Factor
- Neuromodulation 05/2012; 15(3):267. · 1.19 Impact Factor