What are the treatment options for postherpetic neuralgia (PHN)?

From the Guidelines

Post-herpetic neuralgia (PHN) treatment should typically involve a multimodal approach focusing on pain management, with first-line medications including gabapentin, pregabalin, or tricyclic antidepressants, and topical treatments such as lidocaine or capsaicin patches. The treatment of PHN involves a combination of pharmacological and non-pharmacological approaches. According to the 2017 HIVMA of IDSA clinical practice guideline for the management of chronic pain in patients living with HIV 1, gabapentin is recommended as a first-line oral pharmacological treatment of chronic HIV-associated neuropathic pain. Some key points to consider when treating PHN include:

• Gabapentin can be titrated to 2400 mg per day in divided doses, with evidence supporting its effectiveness in improving sleep scores, although somnolence is a common side effect 1.
• If patients have an inadequate response to gabapentin, clinicians might consider a trial of pregabalin, especially for patients with post-herpetic neuralgia 1.
• Topical treatments, such as capsaicin 8% patches, can provide pain relief for at least 12 weeks, with common side effects including erythema and pain 1.
• Tricyclic antidepressants, such as amitriptyline, can also be considered for patients with PHN, although their use may be limited by cardiac toxicity concerns 1.
• Opioids, such as tramadol or oxycodone, may be considered for short-term use in patients with inadequate relief, but their long-term use carries significant risks 1. It is essential to assess pain and health-related quality of life frequently and adjust treatment accordingly, with a focus on achieving substantial pain relief and minimizing adverse effects 1.

From the FDA Drug Label

The efficacy of gabapentin for the management of postherpetic neuralgia (PHN) was established in two randomized, double-blind, placebo-controlled, multicenter studies. The dose can subsequently be titrated up as needed for pain relief to a dose of 1800 mg/day (600 mg three times a day) In clinical studies, efficacy was demonstrated over a range of doses from 1800 mg/day to 3600 mg/day with comparable effects across the dose range The efficacy of pregabalin for the management of postherpetic neuralgia was established in three double-blind, placebo-controlled, multicenter studies Treatment with pregabalin statistically significantly improved the endpoint mean pain score and increased the proportion of patients with at least a 50% reduction in pain score from baseline

The treatment options for postherpetic neuralgia (PHN) include:

• Gabapentin: The dose can be titrated up to 1800 mg/day, with efficacy demonstrated over a range of doses from 1800 mg/day to 3600 mg/day 2
• Pregabalin: Treatment with pregabalin statistically significantly improved the endpoint mean pain score and increased the proportion of patients with at least a 50% reduction in pain score from baseline 3 Key points:
• Gabapentin and pregabalin are effective treatments for PHN
• The dose of gabapentin can be titrated up to 1800 mg/day
• Pregabalin treatment improved mean pain score and increased the proportion of patients with at least a 50% reduction in pain score from baseline

From the Research

Treatment Options for Postherpetic Neuralgia (PHN)

The treatment options for PHN can be classified into several categories, including:

• Pharmacologic treatments:
  • Tricyclic antidepressants (TCAs) 4, 5, 6
  • Anticonvulsants, such as gabapentin 4, 7, 5, 6 and pregabalin 8, 6
  • Local anesthetics, such as lidocaine patches 4, 5, 8, 6
  • Opioids, such as controlled release oxycodone 5
• Interventional treatments:
  • Transcutaneous electrical nerve stimulation (TENS) 8
  • Local botulinum toxin A, cobalamin, and triamcinolone injection 8
  • Intrathecal methylprednisolone and midazolam injection 8
  • Stellate ganglion block 8
  • Dorsal root ganglion destruction 8
  • Pulsed radiofrequency therapy 8
  • Spinal cord stimulation 8
  • Peripheral nerve stimulation 8
  • Paravertebral block 8
• Alternative therapies:
  • Electroacupuncture (EA) 6
  • Osteopathic manipulative treatment (OMT) 6

Mechanism-Based Pharmacologic Interventions

Pharmacologic approaches can be classified into three groups:

• Drugs that act topically in the affected skin area, such as local anesthetics 4
• Drugs that act on nerve excitability and conduction in sensory axons, such as anticonvulsants 4
• Drugs that act on neural damage related synaptic changes, such as TCAs 4

Efficacy and Safety of Treatments

The efficacy and safety of treatments for PHN have been evaluated in several studies, with results showing that:

• Gabapentin is effective in reducing pain and improving sleep and quality of life in patients with PHN 7
• Tricyclic antidepressants, such as nortriptyline, are effective in reducing pain in patients with PHN, but may have adverse effects 5
• Interventional treatments, such as botulinum toxin A injection and stellate ganglion block, may be effective in reducing pain in patients with PHN, but may have adverse effects and require careful assessment of the risk-benefit ratio 8