Varicella-zoster virus (VZV) is the causative agent of varicella, or "chickenpox," and herpes zoster, or "shingles." Most cases of acute herpes zoster are self-limited, although the pain can cause significant suffering, particularly in older adults. Symptoms may be severe enough to interfere with sleep, appetite, or sexual function. In addition, a variable percentage of patients may continue to experience pain for months to years after the resolution of the rash, a condition known as postherpetic neuralgia (PHN). PHN can be quite difficult to treat.
The aim is to find the lowest dose required to ease the pain. This is because the lower the dose, the less likely that side-effects will be troublesome. Possible side-effects vary for the different medicines used. A full list of possible side-effects can be found with information in the medicine packet. Some people don't have any side-effects and some people are only mildly troubled by side-effects that are OK to live with. However, some people are troubled quite badly by side-effects. Tell your doctor if you develop any troublesome side-effects. A switch to a different medicine may be an option if this occurs.