Valacyclovir vs. Valtrex

Valacyclovir is the generic form of the brand Valtrex®.

Both medications work similarly in the body.

General Info
Side Effects
Safety Information

How does Valacyclovir work for Cold Sores?

Valacyclovir is an antiviral drug approved by the FDA to treat oral herpes (cold sores) and genital herpes caused by herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2).

Valacyclovir prevents the herpes simplex virus from building DNA and replicating itself. This reduces the severity of your cold sores and flare-ups, as well as the ability for the virus to transfer between people.

If taken on daily basis, Valacyclovir may reduce the number of outbreaks you experience by up to 80%.

Arrange a private and secure video call with one of our US-licensed doctors today to determine which approach is better for you.

What are some of the more common side effects of valacyclovir?

You may experience side effects with this medication. These side effects are common and typically go away with time and regular use:

  • Headache
  • Nausea
  • Stomach Pain
  • Vomiting
  • Dizziness
  • Side effects in HIV-infected adults may also include:
  • Tiredness
  • Rash

What are the less common but concerning side effects that I should contact a healthcare provider immediately for?

  • Any sign of an allergic reaction
  • Changes in mood or in the way that you are acting
  • Feeling confused
  • Difficulty speaking
  • Feeling shaky, having difficulty moving, or feeling stiff
  • Seizures
  • Bruising or bleeding, dark urine, yellowing of the skin or eyes
  • Severe weakness or fatigue
  • Difficulty passing urine or blood in the urine
  • Hallucinations
  • Valacyclovir does not cure oral herpes. There is no cure for oral herpes.
  • If you get cold sores, it is possible to spread herpes to others even when you don’t have a cold sore that you can see.
    • People will often begin having symptoms 1-2 days before the actual cold sore shows up. This is called a prodrome. The symptoms of a prodrome often include pain, burning, itching, or tingling at the site where the cold sore will appear.
  • DO NOT have intimate or sexual contact with anyone when you have any symptoms that precede a visible infection (“prodrome”: burning, tingling, itching, or pain) or you have a visible cold sore, as you can transmit the herpes virus to them. During these times, it is suggested that you DO NOT:
    • Kiss anyone
    • Share utensils, glasses, towels, products that are applied to the lips (lip balm, lip gloss, lip stick, etc.)
    • Perform oral sex on anyone while you have symptoms of an oncoming infection or a visible herpes outbreak (cold sore) as you can transmit the virus to an uninfected partner’s genitals and give them genital herpes

Do not use valacyclovir for the treatment of oral herpes if you:

  • Are hypersensitive to valacyclovir, acyclovir, or any component of valacyclovir’s formulation
    • Main Ingredient: valacyclovir hydrochloride
    • Inactive ingredients: carnauba wax, colloidal silicon dioxide, crospovidone, FD&C Blue No. 2 Lake, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, povidone, titanium dioxide, edible white ink

If any of the following conditions apply to you, please speak with a healthcare provider in-person about seeking treatment for your oral herpes:

  • Younger than 18 years of age
  • Pregnant or breastfeeding
  • HIV infection or AIDS
  • Kidney or liver problems
  • History of a bone marrow transplant or kidney transplant
  • Weakened immune system not related to HIV infection
  • Aseptic encephalitis or transverse myelitis
  • Urinary retention issues
  • Widespread herpes simplex virus
  • History of seizure disorder

Please tell your physician if you are currently taking any of the following medicines, as they may have an interaction with valacyclovir. If you are taking any of these medicines, you must see a healthcare provider in-person for treatment of your oral herpes:

  • Cladribine
  • Clozapine
  • Foscarnet
  • Mycophenolate
  • Talimogene laherparepvec
  • Tenofovir Products
  • Theophylline Derivatives
  • Tizanidine
  • Zidovudine

Please read the following information regarding the Varicella Virus Vaccine and the Zoster Vaccine:

  • Varicella Virus Vaccine: avoid use of valacyclovir within the 24 hours prior to administration of the varicella vaccine, and avoid use for 14 days after vaccination.
  • Zoster Vaccine (Live/Attenuated): discontinue valacyclovir for at least 24 hours prior to and 14 days after receiving a live attenuated zoster vaccine.