Postherpetic neuralgia (PHN) is a serious complication of herpes zoster that has 
a predilection for older individuals. PHN is often associated with significant 
morbidity, and it can cause insomnia, fatigue, depression and interference with 
daily activities in affected individuals. Treatment for PHN is initiated with 
antivirals during the acute herpes zoster outbreak. Acyclovir (Zoviraxr, 
GlaxoSmithKline), valacyclovir (Valtrex, GlaxoSmithKline) or famciclovir 
(Famvir, Novartis) can be used to treat herpes zoster, and all three have been 
shown to reduce the duration of the herpetic rash and zoster-associated pain. 
These antivirals are most effective when used within the first 72 hours of the 
onset of the rash. Side-effects of these antivirals are low and include nausea, 
vomiting, abdominal pain and headache. Other treatment options for PHN include 
topical analgesics, opioid analgesics, tricyclic antidepressants and gabapentin. 
Because of the complexity of PHN, most patients require a combination of 
treatment modalities for adequate pain relief.