AACHEN, Germany, September 5, 2012 /PRNewswire/ --
Targeted Treatment for Patients Suffering from Postherpetic Neuralgia: It's a Control Thing
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Ask pain patients what they expect from their treatment and the answer is simple: "I want to sleep through the whole night," or, "I want to be able to walk with my wife." They want relief with minimal side effects to master a normal life. Therefore, people with chronic pain may also be attracted to treatments offering flexibility; a sense of control over their disease even when pain management is required for extended periods.
Experts addressing a symposium hosted by Grünenthal at the 14th World Congress on Pain in Milan said topical treatment with a 5% lidocaine medicated plaster, can help improve quality of life for patients with post-herpetic neuralgia (PHN), without a high risk of interacting with other medications or impairing cognitive performance.
PHN is a form of neuropathic pain that occurs after reactivation by the varicella zoster virus (shingles). Some people develop chronic pain after healing from shingles. They suffer from localised symptoms such as constant burning, stabbing and shooting pain, allodynia and hyperalgesia. In up to 20% [1] of people reactivation of the virus occurs at some point in their lives, with between 8% and 19% of these individuals developing PHN.[2]
The burden of PHN is significant. Up to 90% of PHN patients have allodynia which can have a major impact on quality of life and potentially lead to depression.[3],[4] Severe pain has also been shown to impair day-to-day functioning[5] and work performance.[6] Helping patients to live a normal life is a central goal of PHN management. Current pharmacological treatment options for PHN include systemic and topical therapy.
Topical treatment combines proven efficacy and excellent tolerability
Dr Winston de Mello, University Hospital of South Manchester, United Kingdom, said there can be considerable delay in the diagnosis and appropriate treatment of PHN, and many treatment options are typically associated with side effects which are detrimental to patients' quality of life. "The prevalence of PHN increases with age so many of our patients are also taking medications for other conditions. The potential for drug interactions must be considered when selecting a treatment. That is one of the benefits of lidocaine plasters: its topical administration is associated with low systemic side effects," he said.
PHN patients typically suffer from localised pain symptoms such as burning, stabbing, shooting pain, or allodynia and hyperalgesia. Using a medicated plaster allows patients to apply treatment directly to the painful area, Dr de Mello added. Titration is not necessary and patients can use up to three plasters to cover the most painful parts.
Neuropathic pain influences cognitive functioning - how can this impairment be reversed?
The impact of PHN on cognitive processes is currently being studied by researchers at the National Institute of Health and Research (INSERM) at University Regional Hospital, Clermont-Ferrand, France. Speaking at the symposium, Dr Gisèle Pickering gave the audience an insight into some of the key findings emerging from her work. The impact of pain treatments on cognition was assessed in a cohort study including 88 individuals (44 men and 44 women aged 72 years +/- 8). The healthy volunteers were used as a control group while the PHN patients were split into two subgroups: 21 patients were given classical systemic treatment for neuropathic pain (antidepressants, anticonvulsants and opiates), and 21 patients were treated with topical 5% lidocaine administered through a hydrogel plaster.
Reaction time, semantic memory, decision-making, spatial memory and executive function were examined. The research found that reaction time, decision making and semantic memory were impaired in the group of PHN patients who were given systemic treatments. In contrast, no significant changes were found in the performance of the group treated with lidocaine compared to the healthy group.
"This study shows the deleterious effect of treated post-herpetic neuropathic pain on several domains of cognition. These findings are due to the pain itself and also to the side-effects of classical treatments that need to be explored further. Topical treatment with 5% lidocaine medicated plaster is a valuable alternative in post-herpetic pain alleviation and maintains cognitive integrity in this vulnerable population," said Dr Pickering.
Up to 4-year clinical data confirms sustained long-term effect
Prof. Dr Gunnar Wasner, a consultant neurologist at the Department of Neurology and the Division of Neurological Pain Research and Therapy, Christian-Albrechts-University, Kiel, Germany, explained how 5% lidocaine medicated plaster works and discussed new safety data. He said the lidocaine plasteroffers instant cooling and soothing effects and protects the painful area from rubbing. The plaster is easy to administer and can be customised to fit the area of pain. The lidocaine contained in the plaster diffuses continuously into the skin, providing a cumulative local analgesic effect. Lidocaine is a voltage-gated sodium channel antagonist which inhibits the generation and conduction of nerve impulses.[7] The hydrogel plaster acts specifically on abnormally excitable, damaged A- and C-fibres by blocking the sodium channels that they express in high number.[8] This leads to a stabilisation of the neuronal membrane potential, resulting in a reduction of ectopic discharges.[5] The responder rate of 62% is comparable to systemic treatments[9] and more than 80% of responding patients experience pain relief within the first two weeks.[10] In terms of safety, Prof. Wasner said side effects from topical lidocaine are minimal. "All adverse reactions were predominantly of mild and moderate intensity. Of those less than 5% lead to treatment discontinuation."[11] He outlined data from a study which looked at the tolerability of topical lidocaine in patients treated between one and four years.[12] Patients reported between "moderate" and "a lot of" pain relief throughout the treatment period. Investigators rated the change in patients' condition as "very much improved" or "much improved" in about 80% of patients at their final visit.
"The 5% lidocaine medicated plaster has a proven long-term efficiency in neuropathic pain associated with post-herpetic neuralgia (PHN). It has a favourable safety and tolerability profile, allowing long-term use by PHN patients without tolerance problems. Studies show the hydrogel plaster has - due to its topical administration - minimal risk of systemic side effects and patients experience minimal risk of drug-drug interactions. This supports patient compliance with physician-prescribed treatment. The lidocaine plasteris recommended in international guidelines as a first-line treatment for PHN[13]," Prof. Wasner said.
About PHN (post-herpetic neuralgia)
PHN is a neuropathic pain condition that remains after healing of herpes zoster lesions or rash. It manifests itself in various forms of local or peripheral pain symptoms such as constant burning sensations, stabbing and shooting pains, allodynia and hyperalgesia.
About IASP® 14th World Congress on Pain
The IASP® World Congress on Pain is the world's premier conference on pain research and treatment, held this year at the Milan Convention Centre from 27th-31st August. The scientific program consists of a variety of sessions designed to benefit both those who are new to or experienced in pain management through the presentation of promising research and treatment possibilities. For more information on IASP® 2012, please visit http://www.iasp-pain.org/Milan/.
About Grünenthal
The Grünenthal Group is an independent, family-owned, international research-based pharmaceutical company headquartered in Aachen, Germany. Building on its unique position in pain, its objective is to become the most patient-centric company to be a leader in therapy innovation. Grünenthal is one of the last five research-oriented pharmaceutical corporations with headquarters based in Germany which sustainably invests in research and development. These investments amounted to about 25% of revenues in 2011. Grünenthal's research and development strategy concentrates on select fields of therapy and state-of-the-art technologies. We focus on the intensive search for new ways to treat pain better, more effectively and with fewer side-effects than before. Altogether, the Grünenthal Group has affiliates in 26 countries worldwide. Grünenthal products are sold in more than 155 countries and approx. 4,200 employees are working for the Grünenthal Group worldwide. In 2011, Grünenthal reached revenues of 947M €. More information: http://www.grunenthal.com.
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Contact
Product Contact: Jeanette Hübsch, Senior Manager Versatis, Grünenthal Europe & Australia
Phone: +49-241-569-1487, Fax: +49-241-569-3474
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Grünenthal GmbH, 52099 Aachen, Germany, http://www.grunenthal.com
References
1. Donahue JG et al.: The Incidence of Herpes Zoster. Arch Intern Med. 1995 Aug; 7-21; 155 (15):1605-9.
2. Schmader KE: Epidemiology and Impact on Quality of Life of Postherpetic Neuralgia and Painful Diabetic Neuropathy. Clin J Pain. 2002; 18:350-354.
3. Adapted from Davies PS and Galer BS, Drugs. 2004; 64:937-47.
4. Nurmikko T et al. In: Boivie J et al. editors. Seattle (WA). IASP Press 1994:133-41.
5. Johnson RW: Herpes Zoster and Postherpetic Neuralgia. Expert Rev Vaccines. 2010; 9(3s):21-26.
6. McDermott AM et al.: The Burden of Neuropathic Pain: Results from a Cross-sectional Survey. European Journal of Pain. 2006 Feb;10(2):127-35.7. Davies PS, Galer BS: Review of lidocaine patch 5% studies in the treatment of postherpetic neuralgia. Drugs. 2004; 64(9):937-47.
8. Gammaitoni AR et al.: Pharmacokinetics and Safety of Continuously Applied Lidocaine Patches 5%. Am J Health Syst Pharm. 2002 Nov 15; 59(22):2215-20.
9. Baron R et al.: 5% Lidocaine Medicated Plaster Versus Pregabalin in Post-Herpetic Neuralgia and Diabetic Polyneuropathy: an Open-label, Non-inferiority Two-stage RCT.
10. Rehm S et al.: Post-Herpetic Neuralgia: 5% Lidocaine Medicated Plaster, Pregabalin, or a Combination of Both? A Randomized, Open, Clinical Effectiveness Study. Curr Med Res Opin 2010; 26(7): 1607-19.
11. Grünenthal. Versatis® (Lidocaine Plaster 5%) Summary of Product Characteristics Sept. 2011.
12. Sabatowski R et al.: Safety and Efficacy Outcomes of Long-term Treatment up to 4 Years with 5% Lidocaine Medicated Plaster in Patients with Post-Herpetic Neuralgia. Curr Med Res Opin. 2012.
13. Dworkin RH et al. : Recommendations for the Pharmacological Management of Neuropathic Pain : An Overview and Literature Update. Mayo Clin Proc. 2010 ; 85(3)(suppl) : S3-S14.
SOURCE Grunenthal
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