Valtrex vs. Famvir

Are Valtrex and Famvir the Same Thing?

Valtrex (valacyclovir) and Famvir (famciclovir) are antiviral medications used to treat infections caused by herpes viruses, such as herpes zoster (chicken pox and shingles), herpes simplex genitalis (genital herpes), and herpes labialis (cold sores).

Side effects of Valtrex and Famvir that are similar include headache, dizziness, tired feeling, nausea, stomach pain, and skin rash.

Side effects of Valtrex that are different from Famvir include depression, vomiting, joint pain, menstrual pain, stuffy nose, and sore throat.

Side effects of Famvir that are different from Valtrex include gas, diarrhea, sleepiness, itching, and numbness or tingly feeling.

Both Valtrex and Famvir may interact with other antiviral medicines.

Valtrex may also interact with lithium, methotrexate, pain or arthritis medicines, medicines used to treat ulcerative colitis and bowel disorders, medicines used to prevent organ transplant rejection, IV antibiotics, injectable osteoporosis medications, and chemotherapy and cancer medicines.

Famvir may also interact with probenecid.

What Are Possible Side Effects of Valtrex?

Common side effects of Valtrex include:

  • headache,
  • dizziness,
  • tired feeling,
  • depression,
  • nausea,
  • vomiting,
  • stomach pain,
  • joint pain,
  • menstrual pain,
  • skin rash,
  • stuffy nose,
  • or sore throat.

What Are Possible Side Effects of Famvir?

Common side effects of Famvir include:

  • headache,
  • nausea,
  • stomach pain,
  • gas,
  • diarrhea,
  • tired feeling,
  • dizziness,
  • sleepiness,
  • itching or skin rash, or
  • numbness or tingly feeling.

Tell your doctor if you have serious side effects of Famvir including:

  • mental/mood changes (such as agitation, slowed thinking, confusion, hallucinations),
  • changes in the amount of urine,
  • yellowing eyes or skin, or
  • easy bruising or bleeding.

What Is Valtrex?

Valtrex (valacyclovir) is an antiviral medication used to treat infections with:

  • herpes zoster (shingles),
  • herpes simplex genitalis (genital herpes),
  • and herpes labialis (cold sores).

What Is Famvir?

Famvir (famciclovir) is an antiviral drug used to treat infections caused by herpes viruses, including genital herpes, cold sores, shingles, and chicken pox.


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What Drugs Interact With Valtrex?

Valtrex may interact with digoxin, diuretics (water pills), blood thinners, antifungal medications such as ketoconazole, antibiotics such as ampicillin, iron, or methotrexate, and HIV or AIDS medications such as atazanavir and nelfinavir.

Valtrex may interact with, lithium, methotrexate, pain or arthritis medicines, medicines used to treat ulcerative colitis, medicines used to prevent organ transplant rejection, IV antibiotics, antiviral medicines, or cancer medicines. Tell your doctor all medications and supplements you use.

What Drugs Interact With Famvir?

Before taking Famvir, tell your doctor if you are also taking probenecid (Benemid). If you are using probenecid, you may not be able to use Famvir, or you may need dosage adjustments or special tests during treatment.

How Should Valtrex Be Taken?

The dose of Valtrex depends on the condition being treated. Valtrex is taken as caplets that may be taken with or without food.

How Should Famvir Be Taken?

Dosing for Famvir varies. The recommended doses are: recurrent genital herpes: 1,000 mg every 12 hours for one day; recurrent cold sores: 1,500 mg as a single dose; suppression of recurrent genital herpes: 250 mg twice daily; shingles: 500 mg every 8 hours for 7 days; and HIV-infected patients (cold sores or genital herpes): 500 mg twice daily for 7 days.


Is genital herpes contagious? See Answer

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FDA. Valtrex Prescribing Information.

Novartis. Famvir Medication Guide.

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