8 Things to Know About Famciclovir (Famvir) vs. Valacyclovir (Valtrex) for Treating Cold Sores
Key takeaways:
Famciclovir and valacyclovir (Valtrex) are oral prescription medications that treat cold sores in adults. They’re both antiviral medications, and they’re equally effective for helping cold sores go away faster.
You’ll only take famciclovir and valacyclovir for 1 day, as soon as cold sore symptoms appear. But valacyclovir requires two doses, while famciclovir typically only requires one dose.
Unlike famciclovir, valacyclovir is also approved to treat cold sores in children ages 12 and older. And it’s often prescribed off-label to prevent cold sores, too.
Famciclovir and valacyclovir are both available as lower-cost generics. GoodRx can help you save over 80% off the average retail price at certain pharmacies.
Access savings on related medications
Table of contents
Cold sores, also called herpes labialis, are an unpleasant fact of life for many people. As soon as you feel the tell-tale tingling on your lip or inside your mouth, you know one is coming. You may turn to your healthcare provider for medication to get quick relief.
Valacyclovir (Valtrex) and famciclovir (Famvir) are two prescription medications that your provider may choose for you. But which one works better? And what’s the difference between them?
Here, we’ll compare the similarities and differences of famciclovir versus valacyclovir for cold sores.
1. Famciclovir and valacyclovir are both effective for treating cold sores
Cold sores are caused by herpes simplex virus type 1 (HSV-1). Once you’re infected with HSV-1, the virus stays in your body forever — even though you may not have active cold sores. The virus is usually “asleep,” but can awaken now and then, which is when cold sores appear.
Famciclovir and valacyclovir are both antiviral medications. They work by preventing HSV-1 from replicating itself, which stops an infection in its tracks. They’re also both prodrugs, which means they’re turned into an active form in your body after you take them. Famciclovir turns into the active ingredient penciclovir. And valacyclovir turns into the active ingredient acyclovir.
Famciclovir and valacyclovir are both considered first-choice treatments for cold sores. In clinical studies, they both helped cold sores go away about 1 day faster than placebo (a pill with no medication). So they seem to be equally effective, meaning one doesn’t seem to work better than the other. But in order for either medication to work, you need to take it as soon as possible after the first sign of a cold sore.
Good to know: Famvir, the brand-name version of famciclovir, is no longer available. Famciclovir is currently only available as a generic medication.
2. Valacyclovir has more uses than famciclovir
HSV-1 infection is common in children. So having an effective medication to treat cold sore outbreaks before adulthood is key. Both valacyclovir and famciclovir are approved for treating cold sores in adults. But only valacyclovir is approved for use in children ages 12 and older.
Valacyclovir can also be prescribed to prevent cold sores, as well as treat them. This is considered an off-label use, but there are clinical studies showing it’s effective.
3. Famciclovir requires fewer doses to treat cold sores
Valacyclovir and famciclovir dosing schedules are a bit different. The recommended valacyclovir dosage for cold sores is 2 grams by mouth twice daily for 1 day. You’ll either take four 500 mg tablets or two 1 gram tablets for each dose. And you’ll take the 2 doses about 12 hours apart.
But you only need to take one dose of famciclovir for cold sores. The recommended dosage is 1500 mg by mouth as a single dose. This means you’ll take three 500 mg tablets. So famciclovir may be a simpler treatment option for some people. Especially if you have a hard time remembering to take your medication.
Good to know: Famciclovir can also treat frequent cold sores in people living with human immunodeficiency virus (HIV). The recommended dosage in this case is 500 mg by mouth twice daily for 7 days. Just one dose isn’t recommended for this indication.
4. Valacyclovir can be made into a liquid form by your pharmacist
As mentioned above, both famciclovir and valacyclovir are available as oral tablets. And both tablets are a bit larger than average pills. But if you or your child have trouble swallowing pills, valacyclovir can be made into an oral suspension (liquid) by your pharmacist. You may need to use a special pharmacy, called a compounding pharmacy, to have this made. Your provider can help recommend a location in your area.
Valacyclovir suspension can be made in two different doses: 25 mg/mL or 50 mg/mL. So be sure to ask the pharmacist how much of the liquid to measure to make sure you take the right dose of valacyclovir. And only use a dosing spoon from the pharmacy — a household spoon won’t measure the medication properly. The liquid needs to be stored in the refrigerator once it’s made. And you should shake it well before you measure your dose.
5. You may need a lower dose of famciclovir or valacyclovir if you have kidney issues
The kidneys are the main force working to remove both valacyclovir and famciclovir from the body. If you have kidney problems, such as chronic kidney disease, it’s harder for your body to process them. So famciclovir and valacyclovir levels can become too high, which raises the chance of side effects. Lower doses of both medications are recommended if you have kidney problems.
Your famciclovir or valacyclovir dosage for cold sores will depend on your creatinine clearance. This is the test that’s used to measure your kidney function. Your provider will use the results to determine the right dosage of cold sore medication for you.
Good to know: If you have liver problems, no change in your famciclovir or valacyclovir dosage is needed.
6. Famciclovir and valacyclovir have similar side effects
Common side effects of both famciclovir and valacyclovir are headache, nausea, and dizziness. Famciclovir may also cause diarrhea and fatigue. These side effects tend to be mild and resolve on their own.
Both medications can also cause confusion or hallucinations as well as serious blood-related problems. But these side effects are rare. Your provider and pharmacist can help answer any side-effect-related questions you have before you take an antiviral medication for cold sores.
7. You shouldn’t take famciclovir and valacyclovir at the same time
Famciclovir and valacyclovir are both antiviral medications that work in a similar way. They aren’t meant to be taken at the same time, and you’re not to get any extra benefit by taking both medications. You’ll likely just increase the risk for side effects.
That being said, you can use a topical product on your cold sore along with an oral antiviral medication. Over-the-counter options include benzocaine (Orajel) and camphor / phenol (Campho-Phenique). These products can help lessen pain and improve healing of your cold sore. Your provider may also prescribe a steroid cream, such as clobetasol (Temovate), if your cold sores are severe.
8. Both valacyclovir and famciclovir are available as lower-cost generics
Valacyclovir is available as a brand-name medication (Valtrex). But you can also find both valacyclovir and famciclovir as lower-cost generics.
GoodRx can help you save over 80% off the average retail price of the generic versions of valacyclovir and famciclovir. Generic valacyclovir’s price at certain pharmacies is as low as $9.44 with a free GoodRx discount. Generic famciclovir’s price at certain pharmacies is as low as $2.64 with a free GoodRx discount.
The bottom line
Famciclovir and valacyclovir (Valtrex) are oral prescription medications that treat cold sores in adults. You only need to take them for one day, as soon as cold sore symptoms appear. But valacyclovir requires two doses, while famciclovir only requires one dose for most people. They’re equally effective at treating cold sores. But valacyclovir can also treat cold sores in children ages 12 and older. It’s often prescribed off-label to help prevent cold sores, too.
Famciclovir and valacyclovir have similar side effects. And you’ll likely need a lower dose of either medication if you have kidney problems. You shouldn’t take famciclovir and valacyclovir at the same time. But you can use topical products to help with pain while you’re taking an oral antiviral medication.
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References
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