What Are Cold Sores, and How Can You Get Rid of Them? Causes, Treatments, and Pictures
What’s the fastest way to get rid of a cold sore? Can salt or lysine knock it out? Our experts share their go-to treatments and home remedies for cold sores.
famciclovir
Used for Cold Sores, Herpes, Shingles
Used for Cold Sores, Herpes, Shingles
Famciclovir is an antiviral medication used for the treatment of cold sores, genital herpes, and shingles. It works best if it's taken at the first sign of an outbreak.
What is Famciclovir?
What is Famciclovir used for?
- Cold sores (herpes labialis)
- Genital herpes
- Shingles (herpes zoster)
How Famciclovir works
Famciclovir is converted in the body to an active, antiviral medication called penciclovir. Penciclovir prevents the herpes simplex virus (HSV) and varicella-zoster virus (VZV) from making copies of itself, which helps treat viral herpes outbreaks.
Drug facts
| Common Brands | Famvir |
|---|---|
| Drug Class | Antiviral |
| Controlled Substance Classification | Not a controlled medication |
| Generic Status | Lower-cost generic available |
| Availability | Prescription only |
Side effects of Famciclovir
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
- Headache (up to 39%)
- Nausea (up to 13%)
- Diarrhea (up to 9%)
- Stomach pain (up to 8%)
Less Common Side Effects
- Menstrual cramps (females)
- Fatigue or tiredness
- Migraine
- Dizziness
- Gas
- Itchiness
- Rash
Famciclovir serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Allergic reactions
The following Famciclovir side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Incidence not known
Black, tarry stools
bleeding gums
blistering, peeling, or loosening of the skin
blood in urine or stools
chills
clay-colored stools
dark urine
dizziness
joint or muscle pain
loss of appetite
pinpoint red spots on the skin
red, irritated eyes
sores, ulcers, or white spots in the mouth or on the lips
unpleasant breath odor
unusual bleeding or bruising
vomiting of blood
yellow eyes or skin
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common
Bloated, full feeling
burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feeling
confusion as to time, place, or person
excess air or gas in the stomach or intestines
hives or welts
holding false beliefs that cannot be changed by fact
itching skin
mood or mental changes
passing gas
rash
redness of skin
seeing, hearing, or feeling things that are not there
unusual excitement, nervousness, or restlessness
unusual tiredness or weakness
vomiting
Incidence not known
Sleepiness or unusual drowsiness
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Get your GoodRx coupon
$88.58
GoodRx discount
$18.92
Pros and cons of Famciclovir
Pros
- Can be taken with or without food
- Only needs to be taken for one day to treat cold sores and genital herpes in adults without HIV
- Works well for most people to shorten the duration of herpes outbreaks
- Available as a generic, which can be more affordable
Cons
- Not a cure for HSV and VZV infections; only controls the outbreak
- Needs to be taken at the first sign of an outbreak
- Unknown if taking famciclovir can lower your risk of transmitting HSV to someone else
- Can't be used in people younger than 18 years of age
Pharmacist tips for Famciclovir
- Famciclovir works best if it's started at the first sign of an outbreak. For people taking it for recurring herpes outbreaks, it can be helpful to have a prescription available at the pharmacy or a course of medication at home.
- Famciclovir should be started within 72 hours of the first appearance of a shingles-related rash.
- Famciclovir isn't a cure for viral infections, but it can help control infection breakouts and shorten healing time. Continue to follow safe sex practices like using condoms.
- Talk to your healthcare provider if you have an outbreak while you're pregnant or think you may be pregnant. They will instruct you on the best treatment options.
Risks and warnings for Famciclovir
Famciclovir can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
KIDNEY PROBLEMS
- Risk factors: History of kidney damage
Worsening kidney problems have happened in people taking famciclovir who currently have or have had kidney problems. If you have a history of kidney problems, your provider will likely lower your dose of famciclovir to prevent further kidney damage. Make sure you get your blood labs drawn regularly so your provider can monitor how well your kidneys are working.
SEVERE ALLERGIC REACTIONS
- Risk factors: Allergy or intolerance to lactose
Famciclovir tablets contain lactose. Tell your provider before starting this medication if you have a severe allergy or intolerance to lactose. If you experience shortness of breath, difficulty breathing, rash, or swelling of your face, lips, or throat, get medical help right away.
Famciclovir dosage
The average cost for 21 tablets of 500mg of Famciclovir is $27.77 with a free GoodRx coupon. This is 43.84% off the average retail price of $49.45. 
Tablet
Tablet| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 125mg | 30 tablets | $18.92 | $0.63 |
| 250mg | 60 tablets | $39.03 | $0.65 |
| 500mg | 21 tablets | $27.77 | $1.32 |
Typical dosage for Famciclovir
- Cold sores: The typical dose is 1,500 mg by mouth for one dose.
- Genital herpes: The typical dose is 1 gram by mouth twice daily for 1 day. To keep genital herpes from coming back (suppressive therapy), the dose is 250 mg twice daily.
- Cold sores or genital herpes in adults with HIV: The typical dose is 500 mg by mouth twice daily for 7 days.
- Shingles: The typical dose is 500 mg by mouth every 8 hours (3 times daily) for 7 days.
Your dose may differ if you have kidney problems. Ask your provider to see what dose is right for you.
Interactions between Famciclovir and other drugs
Famciclovir may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Famciclovir. Please note that only the generic name of each medication is listed below.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
How much does Famciclovir cost?
To access savings, use a GoodRx coupon and pay just a fraction of the retail price.
Famciclovir (generic)
$18.92
Famciclovir contraindications
Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Famciclovir will not be safe for you to take.
- Allergy to Denavir (penciclovir) cream
What are alternatives to Famciclovir?
There are a number of medications that your doctor can prescribe in place of Famciclovir. Compare a few possible alternatives below.
News about Famciclovir
Cold Sore Medicines: A Guide to Over-the-Counter (OTC) and Prescription Treatments
Bothersome cold sores can be treated with over-the-counter and prescription medications. Learn how to treat cold sores and which medicines may work best for you.
What Are the Chances of Getting Herpes From an Infected Partner?
If your partner has herpes, will you definitely get it? Not necessarily. Learn about genital herpes transmission rates and how you can prevent passing the virus.
How to Treat Shingles: Medication, Pain Relief, Home Remedies and More
There’s no cure for shingles. However, there are treatment options to help manage pain, itching, and other symptoms. Here’s what you need to know.
6 Common Questions About Famciclovir (Famvir) Interactions
Read on for answers to common questions about famciclovir (Famvir) interactions.
8 Famciclovir (Famvir) Side Effects You Should Know About
Read on for famciclovir (Famvir) side effects to know about, from common to rare, and when to reach out to your healthcare team for further guidance.
Famciclovir (Famvir) Dosages for Adults: Your GoodRx Guide
Famvir is an oral medication for infections caused by the herpes virus. Follow our famciclovir dosage guide to learn how to take it and when adjustments may be needed.
8 Things to Know About Famciclovir (Famvir) vs. Valacyclovir (Valtrex) for Treating Cold Sores
Famvir (famciclovir) and Valtrex (valacyclovir) are antivirals that treat cold sores and herpes. Which is more effective? Compare strength and side effects here.
Your Guide to Herpes Creams: Over-the-Counter and Prescription
You can treat cold sores (oral herpes) with the right topicals. Explore prescription and over-the-counter herpes creams, including Abreva and Zovirax.
What to Know If You Have Genital Herpes
Genital herpes is a common sexually transmitted infection. But even though more than 1 in 6 people have it, many are hesitant to talk to their providers and partners about it. And this can make it hard to know what to do when you have it. So we will discuss how to treat outbreaks, tips for talking to your sexual partners about genital herpes, and how to prevent transmission.
Famciclovir images
