Eku Oben, Mercer University College of Pharmacy
Postherpetic neuralgia (PHN) is a complication of herpes zoster, with a 4.2% increase in risk with an increase in age.  Guidelines for the treatment of herpes zoster (HZ) recommend antivirals as first line therapy. However, this treatment has not been shown to prevent PHN. Zostavax® (zoster vaccine live), is 51.3% effective in preventing herpes zoster and 66.5% effective in preventing PHN. It is also recommended for patients 60 years and older in preventing the onset of herpes zoster and PHN.  Topical Lidoderm® (lidocaine) 5% patch is recommended as first-line treatment for PHN.  This study shows the effect of using a combination of drugs to prevent PHN, and the use of a subcutaneous injectable lidocaine formulation, as opposed to the well-studied patch in preventing PHN. 
|Design||Randomized prospective clinical trial; N= 100|
|Objective||To determine the effectiveness of subcutaneous injection of triamcinolone and lidocaine in preventing postherpetic neuralgia (PHN)|
|Study Group||Patients receiving standard treatment for herpes zoster (HZ) (n= 50); patients receiving standard treatment for HZ plus subcutaneous injection of triamcinolone and lidocaine (n= 50)|
|Methods||Patients were asked to quantify the average pain experienced in the last 24 hours on a numeric rating scale (NRS) ranging from 0= no pain to 10= worst pain ever.
Quality of life (QoL) was measured by a medical outcomes study short-form (SF-36).
Follow ups were done at one, three, and six months post rash onset and patients were asked to assess the severity of HZ pain in the past 24 hours.
SF-36 scores were assessed at months three and six after rash, to evaluate QoL.
|Duration||May 1, 2014 – April 30, 2015|
|Primary Outcome Measure||The presence of zoster-associated pain (ZAP) with a numeric rating scale (NRS) score of three, at three months after rash onset|
SD= standard deviation
|Adverse Effects||Common: Self-limiting subcutaneous hemorrhage n= 8 (16%); Pain at injection site n= 7 (14%)|
|Serious: none reported|
|Percentage that discontinued due to adverse events: none reported|
|Study Author Conclusions||Subcutaneous injection of triamcinolone and lidocaine, combined with standard HZ treatment is effective and safe in treating pain caused by HZ and in preventing PHN.|
The study showed a positive effect when standard HZ treatment was combined with subcutaneous triamcinolone and lidocaine in treating HZ and preventing PHN when compared to standard HZ treatment alone. Patients in the subcutaneous group had a lower incidence of zoster associated pain compared to patients in the standard group at month one (p= 0.012), month three (p= 0.014) and month six (0.025). However, this study did not include a placebo subcutaneous injection in the standard group, which could be a limitation in terms of both groups being treated equally. In addition, the small sample size, coupled with the study being carried out in a single center, could be a limitation as it may not be representative of the entire population.
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