What is this medication for?
Acyclovir belongs to the family of medications known as antivirals. Acyclovir is used to treat genital herpes and prevent recurrences of genital herpes. Acyclovir does not cure genital herpes.
Acyclovir is also used for the early treatment of shingles (herpes zoster) and chickenpox (varicella). All of these infections are caused by different types of herpes viruses.
Acyclovir works by stopping the replication of the herpes virus.
Your doctor may have suggested this medication for conditions other than those listed here. As well, some forms of this medication may not be used for all of the conditions discussed here. If you are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.
What form(s) does this medication come in?
Zovirax® by GlaxoSmithKline is available as:
- suspension (oral)
Some medications may have other generic brands available. Always ask your doctor or pharmacist about the safety of switching between brands of the same medication.
How should I use this medication?
Genital herpes: The usual recommended adult dose for genital herpes is 200 mg every 4 hours, 5 times daily for 10 days.
The dose to prevent or reduce recurrences of genital herpes is 400 mg taken twice daily for up to 12 months. Alternatively, the doctor may prescribe 200 mg 3 to 5 times daily. You should start acyclovir as soon as possible following the onset of signs and symptoms of genital herpes.
Shingles: The recommended dose for shingles is 800 mg every 4 hours, 5 times daily for 7 to 10 days. Treatment should be started within 72 hours of onset of the rash or lesions.
Chickenpox (children older than 2 years of age): The recommended dose for chickenpox is based on body weight. The usual dose is 20 mg per kilogram of body weight (not to exceed 800 mg) 4 times daily for 5 days. Therapy should be started within 24 hours of onset of the rash.
It is important you finish all this medication, even if you have started to feel better.
It is important to maintain adequate intake of fluids when taking this medication.
Store this medication at room temperature (59°F to 86°F), protect it from light and moisture, and keep it out of the reach of children.
It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. 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 to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.
Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.
Who should NOT take this medication?
Do not take acyclovir if you are allergic to acyclovir, valacyclovir, or any ingredients of the medication.