Choosing the right prescription

Famvir vs. Valtrex for Herpes Treatment

Valtrex is a brand name of the drug valacyclovir. (Learn More)  Famvir is the brand name of the drug famciclovir. (Learn More)

Both are used to treat shingles, HSV, and outbreaks of genital herpes; neither is a cure for herpes. Instead, they treat the symptoms, reducing discomfort and helping to prevent outbreaks.

There have been some studies comparing the two drugs. One suggested both drugs are similar in effectiveness in treating recurrent genital herpes, with Famvir being the more convenient option.

Meanwhile, a different study suggested that in suppressing genital herpes and associated shedding, Valtrex was slightly more effective. Overall, they are similar in effectiveness.(Learn More)

In addition to Valtrex and Famvir, the drug acyclovir (sold under the brand name Zovirax) is sometimes used to treat herpes. An admittedly old (1998) study showed it to be similar in effectiveness to Valtrex, but it needed to be taken more times throughout the day, making it generally less convenient for most people. It is also worth noting that Valtrex turns into acyclovir through biological and chemical processes.(Learn More)

There is no clear winner when comparing Valtrex and Famvir, which explains why both are still commonly prescribed.(Learn More)

What Is Valtrex?

cold sore

Valtrex, which is the brand name of the antiviral valacyclovir, is used to treat herpes virus infections. While in the body, chemical processes turn valacyclovir into the anti-herpes drug acyclovir, which is what winds up helping the user.

Some of the conditions it treats include:

  • Herpes labialis (also known as cold sores).
  • Herpes zoster (also known as shingles).
  • Herpes simplex (also known as genital herpes or HSV).
  • Chickenpox

It can also be used to prevent infection with cytomegalovirus (CMV) after an organ transplant.

It is important to note that this drug is not a cure for herpes. It also does not prevent a person from spreading herpes.

Valtrex addresses the discomfort of herpes symptoms and allows the body to fight the virus more effectively.

Doctors may adjust dosages for people who are over 65, children, those who have weak immune systems, or those who have a compromised liver, as both Valtrex and Famvir can tax the liver.

What Is Famvir?

Famvir is a brand name for the drug famciclovir. It is an antiviral used similarly, but not identically, to Valtrex.

It treats most of the same conditions, addressing cold sores, herpes outbreaks, and infections. Notably, it is not generally used to prevent CMV after organ transplants.

Like Valtrex, it is not a cure for herpes.


How Are Famvir and Valtrex Different?

While similar, Valtrex and Famvir have a few differences that are evidenced by studies.

A 2006 study came to the conclusion that Valtrex is slightly more effective in the suppression of genital herpes and shedding (spreading of the virus) compared to Famvir.

A 2008 study concluded that a single day of Famvir (1000 mg administered twice daily) was similar to three days of Valtrex (500 mg administered twice daily) in terms of effectiveness in treating recurrent genital herpes. This appears to contradict the previous study, and since fewer doses are involved, it would mean Famvir is slightly more convenient for a patient.

While their mechanisms are slightly different, there is no definitive study or group of studies that indicates one is significantly better or worse than the other.

Alternatives to Famvir and Valtrex


Acyclovir is another drug sometimes prescribed to treat herpes.

A 1998 study came to the conclusion that acyclovir was as effective as Valtrex but less convenient, as it required more doses be taken over the course of the day. It is an antiviral that helps to stop the spread of herpes, but it does not cure it, much like Famvir and Valtrex.

Valtrex, as already noted, actually turns into this drug while in the body. Valacyclovir literally contains the word acyclovir in its name. As such, their mechanisms are extremely similar.

Valtrex is a better option for patients who have difficulties taking their medication on a schedule since it requires fewer doses.

Which Drug Is Best?

There is no evidence strongly suggesting either Famvir or Valtrex is better than the other. As such, it mostly comes down to what your doctor determines is best for you. If one seems to take more of a toll on your body than the other or one proves more effective, that is likely the better option for you.

Neither drug can cure herpes since there is no medically accepted cure for the virus.

Both treat herpes with similar effectiveness. Although some studies indicate one is slightly more effective than the other, other studies do not come to the same conclusion.

Although more studies might eventually prove some instances where one drug is superior to the other, and some patients undeniably react better to one or the other, both are likely to remain primary drugs of choice for most doctors treating herpes. They are both similarly priced and similarly effective for most patients.


Valacyclovir. PubChem Database.

Famciclovir. (December 15, 2017). MedlinePlus.

Valacyclovir (Oral Route): Description and Brand Names. (February 01, 2019). Mayo Foundation for Medical Education and Research (MFMER).

Valtrex Tablets. (June 21, 2017). Medsafe.

Cytomegalovirus (CMV) and Congenital CMV Infection. (June 6, 2018). Centers for Disease Control and Prevention.

Comparative Efficacy of Famciclovir and Valacyclovir for Suppression of Recurrent Genital Herpes and Viral Shedding. (September 2006). Sexually Transmitted Diseases.

Single-Day, Patient-Initiated Famciclovir Therapy Versus 3-Day Valacyclovir Regimen for Recurrent Genital Herpes: A Randomized, Double-Blind, Comparative Trial. (September 1, 2008). Clinical Infectious Diseases.

Famciclovir – Drug Summary. Prescribers’ Digital Reference.

Acyclovir. (May 7, 2019). MedlinePlus.

A Randomized, Placebo-controlled Comparison of Oral Valacyclovir and Acyclovir in Immunocompetent Patients With Recurrent Genital Herpes Infections. (February 1998). The Valaciclovir International Study Group.

Valacyclovir or Famciclovir for Herpes Zoster? (2000). Archives of Family Medicine.

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