Review of Current Guidelines on the Care of Postherpetic Neuralgia
Albany Medical College, Albany, NY 12208, USA. Postgraduate Medicine
(Impact Factor: 1.7).
09/2011; 123(5):134-42. DOI: 10.3810/pgm.2011.09.2469
An unfortunate minority of patients with acute herpes zoster (AHZ) experience pain beyond the typical 4-week duration, and roughly 10% develop the distressing complication of postherpetic neuralgia (PHN), often defined as pain persisting for > 4 months after the onset of the rash. Elderly patients are at increased risk of PHN. The pathophysiology of PHN is complex, likely involving both peripheral and central processes. This complexity may create opportunities for pharmacologic interventions with multiple differing mechanisms of action. Consequently, complementary combinations of pharmacologic agents are frequently more effective than any monotherapy. Current US and international guidelines on the care of patients with PHN are reviewed and interpreted here to facilitate their effective incorporation into the practice of primary care physicians, acknowledging the contrasts that often exist between the clinical trial populations analyzed to craft so-called evidence-based medicine and the individual patients seen in daily practice, many of whom may not have been candidates for those clinical trials. First-line treatments for PHN include tricyclic antidepressants, gabapentin and pregabalin, and the topical lidocaine 5% patch. Opioids, tramadol, capsaicin cream, and the capsaicin 8% patch are recommended as either second- or third-line therapies in different guidelines. Therapies that have demonstrated effectiveness for other types of neuropathic pain are discussed, such as serotonin-norepinephrine reuptake inhibitors, the anticonvulsants carbamazepine and valproic acid, and botulinum toxin. Invasive procedures such as sympathetic blockade, intrathecal steroids, and implantable spinal cord stimulators have been studied for relief of PHN, mainly in patients refractory to noninvasive pharmacologic interventions. The main guidelines considered here are those issued by the American Academy of Neurology for the treatment of postherpetic neuralgia (2004) and general guidelines for the treatment of neuropathic pain issued by the Special Interest Group on Neuropathic Pain of the International Association for the Study of Pain (2007) and the European Federation of Neurological Societies (2010).
Available from: PubMed Central
- "Agents from four therapeutic categories have demonstrated efficacy in clinical trials for relieving the pain associated with PHN. These include tricyclic antidepressants, anticonvulsants, opioids, and topical anesthetics . The immediate-release formulation of gabapentin, an anticonvulsant, was approved by the US Food and Drug Administration (FDA) for the treatment of PHN in 2002. "
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ABSTRACT: Treatment of postherpetic neuralgia (PHN) is more complicated in elderly patients, and multiple daily dosing, complex titration, and high incidences of adverse events can be limiting for many pharmacological treatment options.
The aim of this study was to determine whether the efficacy and tolerability of once-daily gastroretentive gabapentin (G-GR) is similar between elderly patients (≥75 years) and younger patients (<75 years).
Data from two phase III, placebo-controlled studies of 1,800 mg G-GR once daily with dinner in patients with PHN were integrated and analyzed by age subgroups (<75 years, n = 527; ≥75 years, n = 192). Efficacy assessments at endpoint (week 10) included baseline-adjusted change in average daily pain (ADP) and average daily sleep interference (SIS) scores, the proportion of responders (≥30 % pain reduction), and the proportion of patients feeling "Much" or "Very Much" improved on the Patient Global Impression of Change (PGIC).
Compared with placebo, patients in both age subgroups treated with G-GR (placebo/G-GR) had greater reductions in mean ADP (≥75: -21.9/-34.2 %, p = 0.0348; <75: -29.9/-38.3 %, p = 0.0079) and SIS (≥75: -1.3/-2.4, p = 0.0017; <75: -1.8/-2.7, p < 0.0001), more patients were responders (≥75: 30.4/52.0 %, p = 0.0025; <75: 45.0/54.7 %, p = 0.0265), and more felt "Much" or "Very Much" improved on the PGIC (≥75: 20.7/35.0 %, p = 0.0272; <75: 33.6/44.9 %, p = 0.0077). The most common (placebo/G-GR) adverse events (AEs) were dizziness (≥75: 3.3/12.0 %; <75: 1.8/10.4 %), nausea (≥75: 1.0/5.4 %; <75: 2.9/4.2 %), and somnolence (≥75: 0/5.0 %; <75: 3.7/4.2 %). For all patients, AEs rapidly decreased to low steady levels after 4-5 weeks of treatment. The incidence of serious AEs was low and they were reported more frequently in the placebo than in the G-GR group.
Therapy with once-daily G-GR was as effective for treating pain associated with PHN in elderly patients as it was in younger patients. G-GR was well tolerated, and the incidence of the most common AEs did not appear to be age related.
Available from: Hong Soon Kim
- "For the treatment of PHN, both pharmacologic and non-pharmacologic methods have been used . There have been many efforts to optimize the medical treatment of PHN [6,7], thus as a result, the medical treatment of PHN is performed according to the available pharmacologic treatment guidelines or recommendations. Nevertheless, the management of PHN is often suboptimal . "
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ABSTRACT: Postherpetic neuralgia (PHN) is a serious complication resulting from herpes zoster infections, and it can impair the quality of life. In order to relieve pain from PHN, various treatments, including pharmacological and interventional methods have been used. However, little information on the recommendations for the interventional treatment of PHN, along with a lack of nation-wide surveys on the current status of PHN treatment exists. This multicenter study is the first survey on the treatment status of PHN in Korea.
Retrospective chart reviews were conducted on the entire patients who visited the pain clinics of 11 teaching hospitals from January to December of 2011. Co-morbid disease, affected site of PHN, routes to pain clinic visits, parenteral/topical medications for treatment, drugs used for nerve block, types and frequency of nerve blocks were investigated.
A total of 1,414 patients' medical records were reviewed. The most commonly affected site was the thoracic area. The anticonvulsants and interlaminar epidural blocks were the most frequently used pharmacological and interventional methods for PHN treatment. For the interval of epidural block, intervals of 5 or more-weeks were the most popular. The proportion of PHN patients who get information from the mass media or the internet was only 0.8%.The incidence of suspected zoster sine herpete was only 0.1%.
The treatment methods for PHN vary among hospitals. The establishment of treatment recommendation for PHN treatment is necessary. In addition, public relations activities are required in order to inform the patients of PHN treatments by pain clinicians.
Available from: link.springer.com
- "The recommended dosage of pregabalin for PHN is 150–300 mg daily [30, 31]. If pain relief is inadequate following 2–4 weeks of pregabalin at 300 mg/day, the dosage may be increased to 600 mg daily . "
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ABSTRACT: Background and objectives:
There are limited data examining the real-world use of gabapentin and pregabalin for the treatment of post-herpetic neuralgia (PHN). This study examines dosing patterns, therapy outcomes, healthcare utilization and costs of patients with PHN who initiate treatment with gabapentin or pregabalin.
This was a retrospective administrative claims data analysis from July 2005 to February 2010. Patients with PHN initiating gabapentin or pregabalin (index therapy) from January 2006 to February 2009 were identified and were observed for 12 months after index therapy initiation. Outcomes were mean daily dosages of the index therapy, attainment of minimally effective dosages of gabapentin (≥ 1,800 mg/day) or pregabalin (≥ 150 and ≥ 300 mg/day) persistence, discontinuation, index therapy switching, addition of neuropathic pain medications to index therapy, and healthcare resource use and costs.
1,645 patients were identified. The mean daily dosage was 826 mg for gabapentin and 187 mg for pregabalin. Only 52.6 % of patients initiating gabapentin and 56.9 % initiating pregabalin obtained a refill during the post-index period. Approximately 14 % of patients treated with gabapentin reached the target dosage (1,800 mg/day). For pregabalin, 87 % reached ≥ 150 mg/day and 27 % reached ≥ 300 mg/day. On average, patients took 10 weeks to reach 1,800 mg/day gabapentin, and 5.0 and 9.2 weeks to reach ≥ 150 mg/day and ≥ 300 mg/day pregabalin, respectively. Approximately one-third of patients in both index therapy cohorts added a pain medication; more than half added opioids. The percentage of patients switching from either drug (57 %) or adding a therapy (34 %) were similar between index therapy cohorts; opioids were the most common therapy patients switched to or added.
It appears that gabapentin and pregabalin are not used effectively to treat PHN. Suboptimal dosing and discontinuation may be associated with supplementary use of other analgesics, especially opioids.
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