Medically reviewed by Jessica Swirble, PharmD
Last updated on March 28, 2025
Drug Information | Side Effects | Use & Dosage | Request an Online Prescription
Valacyclovir is an antiviral medication primarily used to treat herpes infections, including genital herpes (herpes simplex), cold sores (herpes labialis), and shingles (herpes zoster). It is also used to treat cold sores and chickenpox in children.
Note that valacyclovir will not cure shingles or genital herpes. It is used to reduce pain and to help sores heal faster.
Herpes infections: Valacyclovir is effective in treating herpes simplex virus (HSV) infections, reducing the severity and duration of outbreaks. It can also help alleviate symptoms like pain, itching, and burning associated with herpes.
Shingles (herpes zoster): Valacyclovir can speed up the healing of shingles lesions and reduce the risk of complications such as postherpetic neuralgia.
Chickenpox: Valacyclovir is used to treat chickenpox in children who are at least 2 years old.
Cold sores: Valacyclovir is also indicated to treat cold sores in teenagers who are at least 12 years old.
Valacyclovir is an antiviral drug that becomes acyclovir in the body. Acyclovir is an active antiviral drug that fights against herpes viruses. It works by keeping a virus’ DNA from multiplying. By blocking this process, valacyclovir helps control and suppress herpes outbreaks.
Note that valacyclovir is most effective when started at the first sign of an outbreak or as soon as possible after the onset of symptoms.
Valacyclovir is usually taken orally, with or without food, as directed by your healthcare provider. The dosage and duration of treatment depend on the type and severity of the herpes infection. Follow your healthcare provider's instructions carefully.
For recurrent herpes outbreaks, valacyclovir may be prescribed as a short-term or long-term treatment to prevent future episodes.
Valacyclovir can start relieving symptoms and reducing the duration of herpes outbreaks within a few days of starting treatment. However, complete healing may take longer, especially for shingles. It's important to continue taking valacyclovir as prescribed, even if symptoms improve, to prevent the virus from becoming active again.
In addition to treating herpes infections, valacyclovir may also be used off-label for conditions such as:
Discuss alternate uses of valacyclovir with your healthcare provider.
Valacyclovir is available as an oral tablet in various strengths, including 500mg and 1000mg. It is also available as an oral suspension for children. Generic versions of valacyclovir are available under different brand names.
Valacyclovir is a prescription medication. You will need a valid prescription from a licensed healthcare provider to get this drug.
The use of valacyclovir has been shown to cause side effects in some patients.
Common mild side effects include:
More severe side effects are rare but may include:
If you experience any severe or persistent side effects while taking valacyclovir, seek medical attention promptly.
Before starting treatment with valacyclovir, tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with this drug.
Tell your provider if you are taking these medications or supplements:
You should also mention medical conditions such as:
Tell your provider if you have had a bone marrow transplant.
If you are pregnant, planning to become pregnant, or breastfeeding, consult your healthcare provider before using valacyclovir to assess potential risks and benefits.
You can follow your regular diet while taking valacyclovir. Talk to your healthcare provider about the use of this drug with food, beverages, alcohol, and tobacco.
Drink plenty of water while taking valacyclovir to stay hydrated and support kidney function.
Avoid alcohol while using valacyclovir, as it may increase the risk of side effects or interfere with the medication's effectiveness.
Practice safe sex to reduce the risk of transmitting herpes to others, even while taking valacyclovir.
Your healthcare provider will provide specific instructions regarding the use of valacyclovir with food, beverages, and other medications. It's essential to follow their guidance to ensure the effectiveness of the treatment and minimize the risk of side effects.
If you suspect an overdose of valacyclovir or experience severe symptoms, seek immediate medical attention or contact a poison control center.
Severe symptoms may include:
If an individual has collapsed, is having trouble breathing, or is unresponsive, call 9-1-1 immediately.
Valacyclovir is available in various forms:
The typical starting dose of valacyclovir can vary based on the specific infection being treated, the severity of the infection, and individual patient factors. It is essential to follow your healthcare provider's instructions regarding dosage and administration carefully.
For the treatment of herpes simplex virus (HSV) infections in adults, the typical starting doses may be:
For the prevention of recurrent HSV infections in immunocompetent adults, the typical starting dose may be:
For the treatment of herpes zoster (shingles) in immunocompetent adults, the typical starting dose is:
Your healthcare provider will assess your medical history, current medications, and the nature of the infection to determine the most appropriate dose and duration of treatment for you.
Valacyclovir should be taken exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment without consulting your provider.
If you have any questions about your dosage, contact your healthcare provider. If you want to talk to a provider right away, book an online doctor appointment on Sesame to discuss your concerns.
If you miss a dose of valacyclovir, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose of valacyclovir.
Do not discontinue or alter your valacyclovir dosage without consulting with your healthcare provider. Follow your healthcare provider's instructions regarding dosing and other recommendations for taking valacyclovir.
Store valacyclovir as directed by your healthcare provider or pharmacist. Proper storage is essential to maintain the medication's effectiveness. Valacyclovir should be stored at room temperature, away from excessive heat, light, and moisture.
Keep the medication out of the reach of children and ensure that the container is tightly closed.