Postherpetic neuralgia (PHN) is a condition that affects the nerve fibers in the skin. It is the most common complication of shingles and results from damage to nerve fibers during shingles. The rash and pain from shingles usually lasts about a month. But in people with PHN, the pain from shingles may last for months, and sometimes years, after the shingles rash has healed.

For many people age 50 or older, prescription oral FAMVIR^® (famciclovir) may significantly shorten the duration of PHN, reducing the number of days you have pain. In one clinical study, people age 50 or older who took FAMVIR experienced PHN for about 63 days compared with 163 days for people who did not take FAMVIR. The people who took FAMVIR started taking the medication within 72 hours (3 days) after the shingles rash appeared. FAMVIR is available in easy-to-swallow tablets.

The pain from PHN occurs because of damage to the nerve fibers caused by a reactivation of the varicella zoster virus. Nerve fibers send messages from the skin to the brain. When nerve fibers are damaged during an outbreak of shingles, they are not able to send messages as they normally do. The body may perceive these "mixed messages" as pain.

Age is a primary risk factor for the development of PHN. Older people are more susceptible to PHN than those who are younger. PHN usually does not develop in people under age 50. However, over 40% of patients with shingles age 60 or older develop PHN. After the shingles rash has healed, 75% of people over age 70 have pain at 1 month, and 50% still have pain at 1 year.

During an outbreak of shingles, other risk factors for the development of PHN include:

• Greater pain severity
• Greater rash severity
• Sensory impairment (problems with feeling touch) in the affected skin
• Painful period before the shingles rash appears
• The trigeminal nerve (a nerve in the face) is affected

Prompt treatment with an oral antiviral medication like FAMVIR (within 3 days after the shingles rash appears) may reduce the duration of PHN in many people age 50 or older.

Important Information

Prescription oral FAMVIR^® (famciclovir) is not for everyone. In clinical studies with FAMVIR, the most common reported side effects included headache, nausea, and diarrhea. Ask your doctor if FAMVIR is right for you. If you have kidney problems, your doctor will determine if FAMVIR is appropriate and if so, what the right dose is for you. See the full Prescribing Information for more information about FAMVIR.

FAMVIR should be started within 72 hours (3 days) of the first sign of the shingles rash. Treatment started more than 72 hours (3 days) after the rash has appeared has not been studied.

The efficacy of FAMVIR has not been established for the treatment of ophthalmic shingles or disseminated shingles, or in shingles patients with a compromised immune system.