Famciclovir (oral)

Famciclovir is prescribed by doctors to treat different forms of the infection known as the herpes virus, though the medication relieves pain and discomfort in order to facilitate healing but does not cure the virus.


What is Famciclovir?

Patients prescribed Famciclovir will most likely be familiar with its trade name of Famvir. Available in tablet form for treatment of various herpes infections, the condition known as shingles is the primary disease this drug is prescribed for. Approved for use in 1994, Famciclovir is also available in generic versions.

Famciclovir does not cure the herpes virus, but it does help the sores heal while reducing the discomfort and painful symptoms associated with the virus. Patients who are treated early with Famciclovir have an improved reduction in the recurrence of the virus, with less than five percent of patients seeing repeated symptoms in a six month period.

How does Famciclovir work?

Famciclovir is a prodrug, which means that it does not become an active anti-viral until it is processed by the body. Once processed, Famciclovir turns into a compound known as penciclovir, a compound that stops the herpes virus DNA from reproducing itself and becoming worse and worse. This allows the body to fight the virus off more effectively and reduce the presence of the virus found in the body.

Famciclovir should be prescribed as soon as possible after the first onset of infection. Most patients experience relief from symptoms in two or three days with healing of the sores in about a week. Famciclovir may also be used for suppressive therapy in patients who have repeated outbreaks and are familiar with the signs enough so that they can begin their doses immediately.

Though Famciclovir is not a cure for shingles, cold sores or genital herpes, it does help heal the sores that are a result of the infection of the herpes virus as well as relieve the pain, discomfort and other symptoms caused by the virus while the body fights to get rid of the virus itself.

Conditions Treated

  • Acute herpes zoster
  • Recurrent genital herpes
  • Herpes simplex of the oral-labial
  • Herpes simplex of the genitals
  • Recurrent Herpes simplex of the oral-labial

Type Of Medicine

  • Anti-viral

Side Effects

Medications such as Famciclovir may cause unwanted or unexpected effects on health in some patients. These effects, while typically mild or fleeting, can become problematic in the long-term. It is, therefore, of primary importance that you report any health changes to your physician immediately, especially those listed below:

  • Stools appearing black in color or tar-like
  • Gums that bleed
  • Skin peeling, loosening or blistering
  • Blood in stool or urine
  • Chills
  • Stools the color of clay
  • Coughing
  • Dark colored urine
  • Dizziness
  • Pain in joints or muscles
  • Fever
  • Appetite loss
  • Tiny red dots on skin
  • Bloodshot eyes
  • Throat soreness
  • White lesions on lips or in mouth
  • Halitosis
  • Bruises or bleeding that is unusual or unexpected
  • Vomiting with signs of blood
  • Yellow tinge to skin or eyes

Other side effects, while bothersome, typically resolve themselves over time as the medication is accepted by your body. Your health care professionals may be able to assist you with ways to overcome these unwanted health symptoms. Contact your doctor if you experience:

  • Diarrhea
  • Headache
  • Bleeding
  • Cramps
  • Nausea
  • Abdominal pain
  • Bloating
  • Feelings of pins and needles, tingling, numbness, itching, crawling, burning or prickling
  • Confused demeanor
  • Gas
  • Welts on the skin
  • Paranoia
  • Change in disposition
  • Moodiness
  • Itching
  • Rashes
  • Skin redness
  • Hallucinations
  • Restless or nervous mood
  • Fatigue
  • Vomiting
  • Drowsiness that is unusual

Other side effects than those listed here may also occur in some patients. If you experience a change in your overall health while taking Famciclovir, the best thing to do is contact your physician for assistance.


Patients who have had herpes symptoms in the past and can recognize a recurrence should be aware that the sooner Famciclovir is started the better to prevent a full-blown outbreak. It is best to begin Famciclovir treatment within 48 hours of the first symptoms of shingles, which include burning, blistering, painful skin lesions. Genital herpes symptoms are best treated with Famciclovir within six hours after their first appearance.

Different patients and conditions require different dosage formats of Famciclovir; always follow what your doctor has prescribed specifically for you.


Adult patients will most likely be prescribed 500 milligrams to be taken every eight hours for seven days. Children will have their dosage determined by their physician, if appropriate.

Genital herpesĀ ' recurrent, suppressive therapy

Adult patients will receive a prescription indicating 250 milligrams to be taken twice daily for a twelve month period. Children's prescription for this purpose is varied and determined by their doctor.

Genital herpes' recurrent, treatment therapy

Adult patients will receive a prescription indicating 1000 milligrams to be taken twice in twenty-four hours. Children's prescription for this purpose is varied and determined by their doctor.

Cold sores (herpes labialis) 'recurrent, treatment therapy

Adult patients will receive a prescription indicating 1500 milligrams in a single dose. Children's prescription for this purpose is varied and determined by their doctor.

Herpes infections in HIV patients'recurrent, treatment therapy

Adult patients will receive a prescription indicating 500 milligrams twice daily for one week. Children's prescription for this purpose is varied and determined by their doctor.

Missing a dose of Famciclovir should not prompt you to double dose. Make up the missing dose if you remember far enough away from the time you are supposed to take your next scheduled dose or skip it if the next dose is too close. Resume your regular schedule as soon as possible.


Reactions to Famciclovir or other prescription medications that are hypersensitive in nature should be reported to your physician. If you have also experienced a negative reaction to animals, preservatives, dyes or certain foods, be sure to communicate these as well.

Children under 18 years of age may be prescribed Famciclovir, but this is entirely up to their health care provider, as no data has been vetted that proves safety or effectiveness of this drug for this age group.

Geriatric patients should not experience any greater risks or reduced effectiveness because of their age, except for those with diseases involving the kidneys. These patients should be given Famciclovir with caution, adjusting the dose based on this reduced bodily function.

You should only use Famciclovir if you are pregnant or breastfeeding if you absolutely must; this should be discussed with your healthcare provider, as there are no data sets available to determine any risk you may pass on to your unborn child or infant.

Inform your doctor of any other medications you may be taking, as they may negatively react with Famciclovir by increasing the risks involved in taking this drug or reducing its effectiveness. Include any over-the-counter or vitamin therapies as well as herbal and holistic treatments you receive.

Medical problems such as those listed below can create an unwelcome environment for Famciclovir to do the work it was designed for. It is suggested that you communicate your medical history to the physician prescribing you Famciclovir, especially if you suffer from:

  • Intolerance or inability to absorb galactose or glucose
  • Lactase deficient conditions
  • Kidney diseases


Notify your doctor immediately if you do not experience an improvement in your herpes symptoms within a few days after taking Famciclovir. Keep herpes sores dry and as clean as possible, wearing loose clothing to avoid irritation of the blisters or sores.

Some people become drowsy, dizzy or not as alert as they normally are when they are taking Famciclovir. Use caution before operating machinery, using tools or equipment and driving until you know how you react to this medication. Older adults are especially sensitive to this side effect of Famciclovir.

Avoid sexual activity when you have an outbreak of herpes sores, as Famciclovir does nothing to prevent you from transmitting this virus to your partner. Even if you do not have symptoms, you may spread the genital herpes virus to sexual partners. Barrier methods of protection such as condoms or dental dams are mandatory during all sexual activity, even when your symptoms are at rest. More details on the spread of this virus can be given during a consultation with your healthcare provider.

Alert your physician to any allergies you suffer from as well as your medical history, especially if you have been diagnosed with kidney disease.

Certain forms of Famciclovir contain lactose, so patients who have galactose intolerance or lactase deficiency, which is different from milk intolerances, should let their physician know of this condition prior to taking this medicine.

Avoid vaccinations during your treatment, especially those against a virus known as varicella, as these could be dangerous to your health during treatment with Famciclovir.


Keep the original packaging that your Famciclovir arrived in and use it to store this medication properly. This medication, as well as others, should be kept out of sight and reach of children and pets. Keep this medicine at room temperature, away from exposure to excessive light, heat or moisture. Do not allow Famciclovir to freeze and do not use it if it has become frozen.

Expired or unused Famciclovir dosages should be disposed of properly according to your physician's instructions for safety. If this is not provided to you by your physician, consult with your pharmacist on safe disposal practices.


Famciclovir is an anti-viral drug primarily prescribed to shingles patients to fight the symptoms of the herpes virus. Most patients with recurrent genital herpes as well as those with herpes zoster will benefit from long-term and suppressant therapies with Famciclovir. This drug does not cure the herpes virus nor does it prevent patients from spreading the virus through sexual contact.

By bonding with the cellular DNA of the herpes virus, Famciclovir prevents it from spreading, allowing the body to effectively fight off the infection while healing the sores and alleviating the pain associated with an outbreak. Adult and geriatric patients, as well as older teens, respond well with few side effects to this drug treatment. Caution should be used before prescribing Famciclovir to patients with kidney problems, women who are pregnant, women who may become pregnant or who are breastfeeding.

Attention should be given to patients who experience any kidney related side effects such as changes in urine color, volume or frequency. Hypersensitivity to this drug or others should be communicated to your healthcare professional prior to taking this medication. Due to the lactose content in Famciclovir, those with galactose or lactase issues must inform their doctor.

Be aware that your alertness could be compromised while taking Famciclovir; avoid using power tools, operating machinery or driving until you know how this medication affects your responsiveness. Older adults are more at risk for this side effect and should be monitored.

Other health effects should be reported to your physician right away to prevent any unwanted long-term conditions. If your herpes symptoms do not show improvement within days of taking Famciclovir, alert your medical professional staff.