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Acyclovir oral tablet dosage: A detailed guide

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Form and strengthsDosageFAQsHow it’s takenAcyclovir couponOverdoseAsk your doctor
Acyclovir oral tablet is prescribed for certain viral infections. These include genital herpes, chickenpox, and shingles in adults, as well as chickenpox in some children. It’s taken by mouth two to five times per day.
Medically reviewed by Melissa Badowski, PharmD, MPH, FCCP
Updated on March 3, 2023

This article describes acyclovir oral tablet’s dosages, its strengths, and details on how to take it. You’ll also find information on cost savings and coupon options for acyclovir.

Acyclovir oral tablet is a generic medication. It doesn’t come in a brand-name version. Acyclovir also comes in oral capsule, oral suspension, and injectable forms, but these forms aren’t described in this article. To learn more about these forms, talk with your doctor.

If you want to know more about acyclovir oral tablet, see this overview article. It covers details about the drug’s uses, side effects, and more.

Form and strengths of acyclovir

Acyclovir oral tablet is swallowed. It comes in the following strengths:

  • 400 milligrams (mg)
  • 800 mg

Dosage of acyclovir

This article describes the recommended dosages* for acyclovir oral tablet.

If your doctor prescribes this medication, they’ll determine the dosage that’s best for you. Do not change your dosage of acyclovir oral tablet without your doctor’s recommendation.

* The drugmaker provides these recommended dosages. If your doctor prescribes acyclovir, be sure to take the dosage they prescribe for you.

Usual recommended dosages of acyclovir in adults

Acyclovir is approved to treat genital herpes, chickenpox, and shingles in adults.

Usually, doctors start by prescribing a low acyclovir oral tablet dose. Then, they’ll adjust it over time until the right dosage is reached. Ultimately, your doctor will prescribe the smallest dosage of acyclovir oral tablet that gives the desired outcome.

The table below describes dosages that are commonly prescribed. That said, always take the dosage your doctor prescribes for you. Your doctor will determine the dosage that best meets your needs. Doses are listed in milligrams (mg).

genital herpes, suppression*400 mg2 times per day for up to 12 months
chickenpox800 mg4 times per day for 5 days
shingles (also called herpes zoster)800 mg5 times per day for 7 to 10 days

* This treatment with acyclovir tablet prevents the infection from becoming active again. But to treat a first infection of genital herpes, doctors may use the capsule form of acyclovir. Doctors may also use the capsule form of acyclovir to treat a genital herpes infection that becomes active again.

Dosages of acyclovir in children

Acyclovir is approved to treat chickenpox in children ages 2 to 17 years. Children’s dosages are based on the child’s weight. (For reference, 1 kilogram [kg] equals about 2.2 pounds [lb].)

Body weight in kgApproximate body weight in lbDoseFrequency
 40 kg or less 88 lb or less20 mg per kg (mg/kg)4 times per day for 5 days
more than 40 kgmore than 88 lb800 mg4 times per day for 5 days

For example, assume a doctor prescribes acyclovir oral tablet for a child who weighs 20 kg (about 44 lb). The dosage would be 400 mg, to be taken four times per day for 5 days.

Dosage adjustments for acyclovir

Your doctor will prescribe a dosage of acyclovir oral tablet based on several factors, including:

  • the specific condition being treated and how severe it is
  • age
  • child’s body weight
  • other health conditions

Missed dose of acyclovir

Talk with your doctor or pharmacist right away if you realize you forgot to take a dose of acyclovir oral tablet. They may advise you to take the missed dose. Or they may advise you to skip it and take your next dose as scheduled.

For tips on how to plan your doses of acyclovir oral tablet and avoid missing a dose, read this article. You could also try:

  • downloading a reminder app on your phone
  • setting an alarm
  • putting a note where you’ll see it, such as on your calendar, bathroom mirror, or bedside table

Frequently asked questions

Below are answers to some commonly asked questions about acyclovir oral tablet and its dosage.

Is there a 400-mg or 800-mg dose of acyclovir for cold sores?

Although acyclovir oral tablet isn’t approved to treat cold sores, this is a common off-label use. With off-label use, doctors prescribe a drug for a purpose other than its approved uses.

The same virus that causes genital herpes causes cold sores (oral herpes). The dose of acyclovir doctors prescribe to treat cold sores is based on expert opinion and medical research.

You can talk with your doctor about treatments that may help lessen your symptoms of cold sores.

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What is the acyclovir dosage for an active outbreak?

Acyclovir is approved to treat an active outbreak of genital herpes (an active infection). This type of treatment is sometimes called intermittent therapy. For this use, doctors prescribe the capsule form of acyclovir. The dosage for the capsule is 200 milligrams (mg) five times per day for 5 days.

Your doctor will typically prescribe this treatment to take at the first sign of prodrome. This is a group of symptoms that you notice just before an outbreak. The symptoms at the site of the infection can include:

  • burning
  • itching
  • tingling

Talk with your doctor about when to take acyclovir for an active infection.

Is acyclovir used long term?

Doctors prescribe acyclovir oral tablet as a short-term or long-term treatment. Depending on the condition it’s treating, your duration of treatment may vary. You might take it for as little as 5 days or as long as 12 months.

Your doctor can tell you whether you’ll likely take acyclovir short term or long term.

How acyclovir is taken

You’ll take acyclovir oral tablets two to five times per day.

Your doctor may advise that you take this medication around the same times each day. This can help maintain a consistent amount of the drug in your body. And doing so can help the drug work more effectively.

You can take the tablet with or without food, but you should not crush it.

If it’s hard for you to swallow tablets, view this article. It provides suggestions on how to swallow medications that come in pill form.

Also, be sure to talk with your doctor or pharmacist if you’re having difficulty taking your medication. They can offer recommendations about taking it.

Acyclovir coupon

Visit this page to access Optum Perks coupons and get price estimates for acyclovir when you use the coupons. These coupons can provide significant savings on your prescription costs.

Note: Optum Perks coupons cannot be used with any insurance copays or benefits.

Overdose of acyclovir

It’s important that you do not take more acyclovir oral tablets than your doctor prescribes. Doing so can lead to serious side effects.

Symptoms of acyclovir overdose

Symptoms of an overdose can include:

What to do if you take too much acyclovir

If you think you’ve taken too much acyclovir, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have severe symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

What to ask your doctor

This article describes the usual recommended dosages for acyclovir oral tablet. If your doctor prescribes this medication, they’ll determine the dosage that’s best for you.

Do not change your dosage of acyclovir oral tablet without your doctor’s recommendation. You should take acyclovir oral tablet exactly as your doctor prescribes it.

Let your doctor know if you have concerns or questions about your treatment plan.

Here’s a list of some possible questions you may want to ask your doctor:

  • Will my acyclovir dosage be lower than the recommended dosage if I’m on dialysis?
  • Am I a candidate for a suppressive therapy dosage of acyclovir?
  • Is the acyclovir tablet dosage equivalent to the acyclovir capsule dosage?
  • How long will it take for my acyclovir dosage to ease my shingles symptoms?

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

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