Postherpetic Neuralgia
 

Post-Herpetic Neuralgia

What is post-herpetic neuralgia?

Post-herpetic neuralgia is a nerve pain condition that can result from having shingles. Shingles is a painful rash of blisters on the skin. Shingles itself is caused by the chicken pox virus, which usually lies dormant once having had the chicken pox. The dormant virus can, however, flare up and cause shingles. The onset of shingles oftentimes occurs when someone is under stress. After a number of weeks, shingles usually goes away. Sometimes, however, the nerve pain associated with the shingles continues long after the healing of shingles blisters. This on-going nerve pain is called post-herpetic neuralgia.  

 

Post-herpetic neuralgia, but not necessarily shingles, is associated with older age. That is to say, people can tend to develop shingles at various ages but patients are more likely to develop the complication of post-herpetic neuralgia if elderly.

 

Once someone has had shingles, it typically does not return.  

 

The pain of post-herpetic neuralgia can range in intensity from mild to severe. It is often described as a burning or aching type of pain in the same general area where there were shingles blisters. Patients might complain of sensitivity to touch.

 

Is there a cure for post-herpetic neuralgia?

Post-herpetic neuralgia can last from a few months to years following the shingles blisters. There is no outright cure that can shorten this time frame. Treatment goals are to manage the symptoms to the point that they are tolerable.  

 

Therapies & procedures for post-herpetic neuralgia

Common symptom management therapies include non-steroidal anti-inflammatory medications, lidocaine patches, antidepressant medications, anticonvulsant medications, opioid medications, cognitive behavioral therapy, and chronic pain rehabilitation programs.

 

Most of these therapies have been shown in research to be effective in reducing pain. It is important to note, however, that ‘effective’ in this context does not mean ‘curative.’ Rather, it means that many of these therapies are helpful in reducing pain, but some degree of pain will typically remain. Also, it is important to note that these therapies, even the ones with demonstrated effectiveness, are not all equally effective. The research shows that some are more effective than others.

 

Anti-inflammatory medications

Conventional wisdom in healthcare tends to recommend a trial of anti-inflammatory medications for the use of post-herpetic neuralgia pain. However, there is little research as to whether or not anti-inflammatory medications are helpful in reducing pain.  

 

Lidocaine patches

In their review of the research on different medications for use with post-herpetic neuralgia, Hempenstall, et al., Hempenstall, Nurmikko, T. J., Johnson, R. W., A’Hern, R. P., & Rice, A. S. (2005). Analgesic therapy in postherpetic neuralgia: A systematic review. PLOS Medicine, 2, e165. found only one small clinical trial of lidocaine patches. The trial showed that it was helpful in reducing pain. Other reviewers Khaliq, W., Alam, S., Puri, N. K. (2006). Topical lidocaine for the treatment of postherpetic neuralgia. [Cochrane Review]. In Cochrane Database of Systematic Reviews, 20067 (2). Retrieved July 7, 2012, from The Cochrane Library, Wiley Interscience. conclude that there is insufficient research evidence to know whether lidocaine patches are effective. As such, most clinicians will recommend the use of lidocaine patches on a trial basis.  

 

Antidepressant medications

Roughly, there are three types of antidepressant medications. Serotonin norepinephrine reuptake inhibitors (SNRI’s) are the newest type of antidepressant medications. SNRI’s are typically the ones that are advertised for use in diabetic neuropathy or fibromyalgia. Selective serotonin reuptake inhibitors (SSRI’s) are the second type and are a little older. They were originally developed for use in depression. Tricyclic antidepressants are the third type. They are the oldest type of antidepressants. They too were originally developed for use in depression. However, they also have a long history of use for chronic pain.  

 

Surprisingly, for the treatment of chronic pain in general, the most effective type of antidepressant medication is the oldest type. The oldest type is the tricyclic antidepressants.  

 

In their review of the research, Hempenstall, et al., 2005, 1 found that the tricyclic antidepressants were largely the most effective medication for post-herpetic neuralgia as well. They used a statistic call ‘number needed to treat’ (NNT). This statistic is a measure of how effective a treatment is. It represents the number of people who must be treated with a particular treatment before one of them obtains at least a 50% reduction in their symptoms. Hempenstall, et al., found that tricyclic antidepressants tend to have a NNT of between 1.6 and 4.15, depending on the research study they reviewed. That is to say, approximately two to four people will need to be treated with a tricyclic antidepressant before one of them will have their pain symptoms reduced by at least 50%. As points of comparison, they found that gabapentin, another type of medication commonly used for pain, has an NNT of between 3.22 and 5.04; pregabalin has an NNT of 3.42 and 6.23; opioid, or narcotic, medications have an NNT of 2.5 and 2.79. As such, they show that tricyclic antidepressant medications tend to be more effective than gabapentin and pregabalin, and at least as effective, if not more effective, than opioid medications.  

 

In a randomized clinical trial comparing opioid medications to tricyclic antidepressants for the treatment of post-herpetic neuralgia pain, Raja, et al., Raja, S. N., Haythornwaite, J. A., Pappagallo, M., Clark, M. R., Travison, T. G., Sabeen, S., Royall, R. M., & Max, M. B. (2002). Opioids versus antidepressants in postherpetic neuralgia: A randomized, placebo-controlled trial. Neurology, 59, 1015-1021. found no statistical difference between the two types of medications in terms of pain reduction.  

 

Anticonvulsant medications

Anticonvulsant medications are medications that were originally developed for the management of seizures. However, they have also been shown to be helpful in managing the pain of post-herpetic neuralgia.  

 

Hempenstall, et al., 1 found anticonvulsant medications to be effective. Such medications have an NNT of between 3.22 and 6.23. That is to say, three to six people will have to be treated before one of them achieves pain reduction of at least 50%.

 

Opioid medications

Opioid, or narcotic, pain medications are commonly used in clinical practice. Hempenstall, et al., 1 reviewed two clinical trials of opioids for post-herpetic neuralgia and found that they had an NNT between 2 and 3. That is to say, two to three people will have to be treated before one of them will achieve at least a 50% reduction in pain.  

 

Cognitive behavioral therapy

Cognitive behavioral therapy (CBT) is a standard and effective treatment for chronic pain syndromes in general. Morley, S., Eccleston, C., & Williams, A. (1999). Systematic review and meta-analysis of randomized controlled trials of cognitive behavior therapy and behavior therapy for chronic pain, excluding headache. Pain, 80, 1-13. While there are no controlled trials of CBT for post-herpetic neuralgia, it is commonly pursued on the assumption that it is effective, based on its demonstrated effectiveness for other pain conditions. Kost, R. G. & Straus, S. E. (1996). Post-herpetic neuralgia – pathogenesis, treatment, and prevention. New England Journal of Medicine, 335, 32-42.

 

Chronic pain rehabilitation programs

Chronic pain rehabilitation programs are interdisciplinary programs designed to help patients learn to self-manage chronic pain. Their goals are to reduce pain, reduce secondary problems associated with living with chronic pain, reduce the use of narcotic medications, and return to work or some other meaningful regular activity. They are effective in achieving these goals, and there is high quality research evidence demonstrating their effectiveness. Gatchel, R., J. & Okifuji, A. (2006). Evidence-based scientific data documenting the treatment and cost-effectiveness of comprehensive pain programs for chronic non-malignant pain. Journal of Pain, 7, 779-793. However, there are no clinical trials assessing the effectiveness of chronic pain rehabilitation programs solely for post-herpetic neuralgia.

 

Author

Murray J. McAllister, PsyD, is the executive director of the Institute for Chronic Pain. The Institute for Chronic Pain is an educational and public policy think tank. Its purpose is to bring together thought leaders from around the world in the field of chronic pain rehabilitation and provide academic-quality information that is also approachable to all the stakeholders in the field: patients, their families, generalist healthcare providers, third party payers, and public policy analysts. Its aim is to change the culture of how chronic pain is managed through education and consultation efforts that advocate for the use of empirically supported conceptualizations and treatments of chronic pain. He also blogs at the Institute for Chronic Pain Blog.

 

References

Last Updated on Sunday, 30 October 2016 18:24

Published on Friday, 27 April 2012 13:39

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