To treat shingles (herpes zoster) and recurrent genital herpes.
Famciclovir interferes with the activity of specific enzymes needed for the replication of DNA in viral cells, thus preventing the virus from multiplying.
For shingles (herpes zoster): 500 mg every 8 hours for 7 days. The effectiveness of famciclovir in treating herpes zoster is usually determined after 2 days of regular use. The best effect is achieved if the medicine is prescribed immediately after the diagnosis is made. For recurrent genital herpes: 250 mg twice a day for up to 1 year. It should be taken at the first sign of recurrence.
Within 1 hour.
No special restrictions.
Store in a tightly sealed container away from heat, moisture, and direct light.
Take it as soon as you remember. If it is near the time for the next dose, skip the missed dose and resume your regular dosage schedule. Do not double the next dose.
Take it as prescribed for the full treatment period, even if you feel better before the end of therapy. The decision to stop taking the drug should be made by your doctor.
This drug is not intended for prolonged use, but under some circumstances it may be used for an extended period for the suppression of a chronic herpes virus infection.
No special problems expected except for older persons with impaired kidney or liver function.
Famciclovir may cause dizziness and fatigue. Do not drive or engage in hazardous work until you determine how the medicine affects you.
No special precautions are necessary.
Studies of the use of famciclovir in pregnant women have not been done. Consult your doctor about the risk of taking famciclovir during pregnancy.
Famciclovir may pass into breast milk; avoid or discontinue use while nursing.
The safety and effectiveness of famciclovir for anyone under 18 have not been established. It should be used only under close medical supervision.
This medicine is not recommended for use if you have had a bone marrow transplant or a kidney transplant. Before taking famciclovir, tell the doctor if your immune system is compromised. Do not take famciclovir if you have had an allergic response to it previously. Keep the affected area of skin clean and dry; wear loose-fitting clothing. Your doctor may periodically wish to take blood tests to evaluate your kidney function.
No cases of overdose have been reported.
An overdose is unlikely to occur. However, if you have any reason to suspect an overdose, call your doctor, emergency medical services (EMS), or the nearest poison control center immediately.
Other drugs may interact with famciclovir. Consult your doctor for specific advice if you are taking probenecid or any other prescription or over-the-counter drug.
No known food interactions.
Consult your doctor if you have any disorder or condition associated with a weakened immune system, such as HIV infection or AIDS. Use of famciclovir may cause complications in patients with impaired liver or kidney function, since these organs work together to remove the medication from the body.