Famvir for genital herpes (Famciclovir)
Complete patient guide for uses, dosage, side effects, and safety information
Prescription RequiredQuick Facts
What Is Famvir for genital herpes Used For?
Famvir is an antiviral medicine designed for adults and adolescents to combat genital herpes infections caused by herpes simplex 1 or herpes simplex 2 viruses.
Primary Uses
Famvir treats active outbreaks of genital herpes and helps suppress (prevent) recurring episodes. It’s commonly used for people who experience frequent genital herpes attacks to reduce their frequency and severity.
How It Works
While Famvir doesn’t cure the viral infection, it helps relieve symptoms and shortens the duration of outbreaks. The medication works best when started as soon as possible after the first symptoms appear.
Good to know: Famvir is not addictive and is only available with a doctor’s prescription.
How to Take Famvir for genital herpes
Famvir tablets should be swallowed whole with a full glass of water and can be taken with or without food. There’s no need to chew or crush the tablets.
Dosage Instructions
For treating an outbreak: Start within 6 hours of first symptoms. Options include: Two 500 mg tablets twice daily for one day, OR Two 250 mg tablets initially, then one 250 mg tablet every 12 hours for 3 more doses, OR One 125 mg tablet every 12 hours for 5 days. For preventing outbreaks: Take one 250 mg tablet twice daily continuously as prescribed. Take doses 12 hours apart during waking hours, but never less than 6 hours apart.
What If You Miss a Dose?
Take the missed dose as soon as you remember, then continue with your regular schedule. Don’t take two doses within one hour of each other – skip the missed dose if this would happen.
Important: Never take a double dose to make up for a missed one, as this may increase your risk of side effects.
Available Tablet Strengths
Side Effects
Like all medications, this medicine can cause side effects. Most are mild and temporary, but some require medical attention.
Common Side Effects
These side effects occur relatively frequently and usually don’t require emergency care:
- headache
- dizziness
- nausea or vomiting
- abdominal pain
- diarrhea
- itching or itchy rash
- abnormal liver function test results
Seek immediate medical attention if you experience:
- rash on other parts of your body
- extreme sleepiness or confusion (especially in older people)
- hallucinations
- painful or swollen joints
- muscle aches, tenderness, or weakness not caused by exercise
- yellowing of skin or eyes (jaundice)
- heart palpitations
- swelling below skin surface (face, eyes, throat)
- unexplained bruising or bleeding
- severe skin blistering
- purple patches or burning skin
- seizures or fits
- severe allergic reactions (difficulty breathing, swelling, blue discoloration)
Important Warnings
Before taking Famvir, it’s crucial to discuss your medical history and current health conditions with your doctor to ensure safe use.
Who Should Not Take Famvir for genital herpes
Don’t take Famvir if you’re allergic to famciclovir, penciclovir (a related antiviral), or any other ingredients in the tablets. Signs of allergic reaction include difficulty breathing, swelling of face/lips/tongue, or skin rash and hives. Don’t use expired medication or tablets from damaged packaging.
Medical Conditions to Discuss
Tell your doctor if you have problems with your immune system, kidneys, or liver, as special precautions may be needed. Also mention if you’re lactose intolerant, as 125 mg and 250 mg tablets contain lactose (500 mg tablets don’t).
Pregnancy and Breastfeeding
Famvir should not be used during pregnancy unless absolutely necessary. Your doctor will discuss the potential risks if you’re pregnant, planning to become pregnant, or breastfeeding, and will advise based on your individual situation.
Drug Interactions
Several medications can interact with Famvir, potentially affecting how well it works or increasing side effects.
- probenecid (used for gout and to increase penicillin levels)
- raloxifene (used for osteoporosis)
- medicines that can affect your kidneys
Alcohol & Driving
Famvir can affect your ability to drive or operate machinery safely, so take precautions until you know how the medication affects you personally.
Alcohol
No specific alcohol interactions are mentioned, but consult your doctor or pharmacist for advice before consuming alcohol while taking any medication.
Driving and Operating Machinery
Be careful when driving, operating machinery, or doing jobs requiring alertness, as Famvir can cause dizziness, sleepiness, or confusion.
Storage
Store Famvir tablets in their original container in a dry place at room temperature. Avoid storing in bathrooms, near sinks, in cars, or on window sills, as heat and dampness can damage the medication. Keep out of reach of children, preferably in a locked cupboard at least 1.5 meters above ground level.
Overdose Information
If you suspect an overdose, immediately contact your doctor, call the Poisons Information Centre (13 11 26), or go to your nearest hospital emergency department. Bring the medication package with you. Taking too much Famvir may affect your kidneys and, in people with existing kidney problems, could rarely lead to kidney failure if the dose isn’t properly adjusted.
Frequently Asked Questions
Famvir works best when started as soon as possible after symptoms begin, ideally within 6 hours of the first signs of genital herpes. It helps relieve symptoms and shorten their duration, though it doesn’t cure the viral infection.
Yes, Famvir tablets can be taken with or without food. There’s no need to chew or crush the tablets – just swallow them whole with a full glass of water.
No, Famvir is not addictive. It’s an antiviral medication that’s only available with a doctor’s prescription.
Don’t stop taking Famvir or change your dosage without checking with your doctor first. If you stop suddenly, your condition may worsen or you may experience unwanted side effects.
No, taking Famvir does not prevent you from spreading the herpes virus to another person. You should practice safer sex, including using condoms, especially when symptoms are present, even after starting Famvir.
Take the missed dose as soon as you remember, then take your next tablet at the usual time. Don’t take two doses within one hour of each other – skip the missed dose if this would happen. Never take a double dose to make up for a missed one.
Tell your doctor if you have kidney problems, as they may need to give you a lower dose. Taking too much Famvir may affect your kidneys, and in people with existing kidney problems, it could rarely lead to kidney failure if the dose isn’t properly adjusted.
Important Disclaimer
This information is intended for general educational purposes only and should not be considered medical advice. Always consult your healthcare provider or pharmacist before starting, stopping, or changing any medication.
If you think you may have a medical emergency, call your doctor or emergency services immediately.