Description
Famcyclovir is a prescription drug used to treat viral infection, also called an antiviral. It is typically given for the treatment of:
- Prevention of herpes simplex infection
- Treatment of herpes simplex infection
- Treatment of herpes zoster (shingles)
- Treatment of varicella infection in patients with HIV
Once in the body, Famvir is converted to the active molecule penciclovir. Penciclovir incorporates itself into the viral protein responsible for helping the virus to replicate. This action prevents the formation of more viral particles and slows or stops the infection.
Fact Table |
Formula |
C14H19N5O4 |
License |
US FDA |
Bioavailability |
75–77% |
Legal status |
Rx-only |
Chemical Name |
Famciclovir |
Elimination half-life |
2–2.3 hours |
Dosage (Strength) |
125mg, 250mg, 500mg |
Pregnancy |
Consult Doctor |
Brands |
Famvir |
Protein binding |
20–25% |
PubChem CID |
3324 |
MedlinePlus |
a694038 |
ChEBI |
4974 |
ATC code |
J05AB09 |
DrugBank |
DB00426 |
KEGG |
D00317 |
Routes of administration |
Oral |
Directions
The dosage varies based on the type of virus and the location of the infection. Take Famvir exactly as prescribed by your doctor. Take Famvir with a full glass of water for each dose.
Ingredients
The active ingredient is famciclovir.
Interactions
Common drug-drug interactions with this medication may include:
- Cladribine
- Talimogene Laherparepvec
- Varicella Virus Vaccine
- Zoster Vaccine
If you have taken any of the above, tell your doctor or pharmacist before starting Famvir.
Cautions
Tell your doctor if you have a history of kidney problems before starting this drug. The dose may need to be reduced in people with impaired kidney function.
Famvir tablets contain lactose. Use caution if you have lactose intolerance.
Side Effects
There are many potential side effects, including:
- Abnormal hepatic function tests
- Anaphylactic shock
- Anaphylaxis
- Anemia
- Angioedema
- Cholestatic jaundice
- Confusion
- Delirium
- Diarrhea
- Disorientation
- Dizziness
- Drowsiness
- Dysmenorrhea
- Erythema multiforme
- Eyelid edema
- Facial edema
- Fatigue
- Flatulence
- Hallucination
- Headache
- Hypersensitivity angiitis
- Increased serum ALT
- Increased serum AST
- Increased serum bilirubin
- Leukopenia
- Migraine
- Nausea
- Neutropenia
- Palpitations
- Paresthesia
- Periorbital edema
- Pharyngeal edema
- Pruritus
- Seizure
- Skin Rash
- Stevens-Johnson syndrome
- Thrombocytopenia
- Toxic epidermal necrolysis
- Urticaria
- Vomiting
Tell your doctor or pharmacist if you experience any of the above while taking Famvir.
References
Famvir [package insert]. East Hanover, NJ: Novartis Pharmaceuticals Corp.; 2006.
Frequently Asked Questions about Famvir (Famciclovir)
What is Famvir used for?
Famvir is used to treat infections caused by herpes viruses, including genital herpes, cold sores, and shingles.
How should I take Famvir?
Take Famvir as directed by your doctor, usually with or without food. The usual dosage is 500mg 2-3 times a day for a week.
Can Famvir cure herpes?
No, Famvir can help to control herpes symptoms, but it does not cure the virus.
What are the possible side effects of Famvir?
Common side effects include headache, nausea, and diarrhea. Serious side effects are rare but may include kidney problems.
Can I drink alcohol while taking Famvir?
It's best to avoid alcohol as it can increase the risk of Famvir's side effects.
How long does it take for Famvir to work?
It may take up to 2 days for Famvir to start reducing symptoms of herpes infections.
Can I take Famvir during pregnancy?
Talk to your doctor to determine if Famvir is safe for you during pregnancy, as there is no sure consensus on its safety
Can Famvir prevent the spread of herpes?
Famvir can help to reduce the spread of herpes when taken as directed.
What should I do if I miss a dose of Famvir?
Take the missed dose as soon as you remember, but skip it if it's almost time for your next dose.
Can I crush or split Famvir tablets?
It's best to take Famvir tablets whole, but consult with your pharmacist if you have difficulty swallowing them.
About Dr. Conor Sheehy (Page Author)
Dr. Sheehy (BSc Molecular Biology, PharmD) works a clinical pharmacist specializing in cardiology, oncology, and ambulatory care. He’s a board-certified pharmacotherapy specialist (BCPS), and his experience working one-on-one with patients to fine tune their medication and therapy plans for optimal results makes him a valuable subject matter expert for our pharmacy. Read More....
IMPORTANT NOTE:
The above information is intended to increase awareness of health information and does not suggest treatment or diagnosis. This information is not a substitute for individual medical attention and should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. See your health care professional for medical advice and treatment.
Product Code : 1519