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Antiviral Medications

Studies have suggested that prompt initiation of antiviral medication within 72 hours of the onset of the rash contributes to hastened rash healing and reduced severity and duration of shingles related pain - especially in more severe infections that are accompanied by greater damage to the nerves - and may reduce or prevent the occurrence of postherpetic neuralgia.

Because postherpetic neuralgia usually does not occur in persons under the age of 50, young adults and children with competent immune systems do not require antiviral therapy aimed at preventing this problem. In addition, some guidelines recommend that antiviral treatment be reserved for persons who are holder, have moderate or severe rash or pain, or have involvement of the eye area.

Available antiviral medications include:

• Famciclovir (Famvir) - usual dose is 500mg three times daily for 7 days
• Valacyclovir (Valtrex) - usual dose is 1000mg three times daily for 7 days
• Acyclovir (Zovirax) - usual dose is 800mg five times daily for 7-10 days

Intravenous acyclovir therapy is the therapy of choice for:

• Severely immunocompromised persons, including those who have received stem cell transplant within 4 months
• Any transplant recipient receiving anti-rejection therapy
• Patients with suspected dissemination (i.e., encephalitis or pneumonitis)
• Children with recurrent disease

Pain Medications for Postherpetic Neuralgia

Because people with postherpetic neuralgia experience various types of pain, it is thought that there are multiple pathophysiological mechanisms involved including the peripheral and central nervous systems. Postherpetic neuralgia is often treated with a combination of medications that work in different ways to best relieve the symptoms - and one regimen may work better for one person than another. Unfortunately, 40-50% or persons with postherpetic neuralgia do not respond to any treatment.

Medications that may be used to relieve pain associated with postherpetic neuralgia include:

• Opioids - These agents include Oxycodone and Morphine and have been shown to be very effective in relieving postherpetic neuralgia in some patients. Side effects include sedation and constipation.

• Tricyclic antidepressants (TCAs) - These medications are thought to relieve pain by inhibiting the reuptake of chemical messengers known as neurotransmitters , such as norepinephrine and serotonin, thereby inhibiting the spinal nerves involved with pain perception. Side effects vary in severity among the available TCA medications but may include sedation, dry mouth, low blood pressure, and especially concerning among older persons - dizziness, confusion and glaucoma. Generally, the TCA medication is administered for several months before attempting dosage reduction. Available TCAs include:

  • Amitriptyline (Elavil)
  • Nortriptyline (Pamelor)
  • Desipramine (Norpramin)
  • Maprotiline (Ludiomil)

• Anticonvulsants - These medications have been used to treat several types of neuropathic pain. Side effects include tiredness, dizziness, swelling of the ankles (peripheral edema), and dry mouth. The most commonly used anticonvulsants for postherpetic neuralgia are:

  • Gabapentin (Neurontin) - usually started as a single daily dose and can be gradually increased to a maximum dose of 1200mg three times daily if needed
  • Pregabalin (Lyrica) - usual initial dose is 75mg at bedtime or twice daily, then increased by 75mg twice daily every 3 days as needed to a maximum dose of 300mg twice daily. Most common side effects are sedation, dizziness and swelling of the legs and feet (peripheral edema).