How much acyclovir should I take for cold sores?

Acyclovir is an antiviral medication used to treat herpes infections, including cold sores. It comes in the following forms:

• oral tablets
• oral capsules
• oral suspension (liquid)
• topical cream 
• topical ointment
• injection (intravenous [IV])

Acyclovir is only available with a prescription. It is a generic drug, but it comes in the brand names Zovirax and Sitavig.

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What is the dosage of acyclovir for cold sores?

The dosage of acyclovir your doctor prescribes will vary depending on the form of the medication and how severe the infection is.

For an active outbreak of cold sores, doctors typically prescribe 200 mg of acyclovir, taken five times per day, for a total of 1,000 mg daily. Or they may prescribe 400 mg of acyclovir, taken three times per day. You will usually continue either dosage for 7 to 10 days. For children, the dosage may vary based on their age and weight.

Some people who experience multiple cold sore outbreaks each year may decide to take acyclovir preventatively. This means they’ll take the drug every day to decrease their chances of getting cold sores. The dosage of acyclovir, when used preventatively, is 400 mg taken twice per day.

Can I take more acyclovir to make my cold sore go away faster?

Taking more acyclovir will most likely not speed up the healing time for a cold sore. It is not safe to double or increase your acyclovir dosage unless your doctor or pharmacist recommends it.

While it may seem that taking more acyclovir could speed up healing, taking more than the recommended dosage of acyclovir can lead to side effects, like nausea and vomiting, or overdose.

Acyclovir can cause a severe allergic reaction and has a boxed warning not to take the drug again if you’ve had an allergic reaction to it. Taking it again could be fatal (cause death).

If you don’t notice any relief in your symptoms after 7 to 10 days of taking acyclovir, or if your symptoms worsen, talk with your doctor. 

How fast will a cold sore go away with acyclovir?

How quickly acyclovir works to make a cold sore go away depends on the severity of the cold sore and when you start taking the medication. If you take acyclovir at the first signs of a cold sore outbreak, such as tingling or itching, you may notice reduced pain and fewer new blisters. But complete healing of cold sores can take 2 to 6 weeks. 

How can I make my cold sore go away faster?

If you don’t notice your cold sore starting to heal after about a week of taking acyclovir, talk with your doctor. 

They may recommend a different antiviral medication, such as valacyclovir (Valtrex) or famciclovir. These antiviral medications are similar to acyclovir but have different dosing schedules. They may work better for some people.

In addition to taking acyclovir or a different antiviral medication, you can also try the following to help clear up cold sores faster.

• Use antiviral creams or ointments: Applying over-the-counter antiviral creams, like docosanol (Abreva), can help reduce healing time. 
• Keep the cold sore clean and dry: Gently clean the cold sore area with soap and water, ensuring that it stays dry to prevent further irritation or infection.
• Use sun protection and try to avoid stress: Common cold sore triggers include stress, fatigue, and excessive sun exposure. Using lip balm with SPF may help speed up healing and prevent new blisters.
• Avoid touching the sore: Avoid picking or scratching the cold sore, as this can delay healing and cause the virus to pass to other areas of your body or to other people.

If you keep getting new cold sores or they don’t seem to heal with typical treatments, talk with your doctor. They may recommend alternative options.

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Summary

Acyclovir is an antiviral medication that healthcare professionals sometimes prescribe to help clear up cold sores.

For an active outbreak of cold sores, doctors typically prescribe 400 mg of acyclovir, taken 3 times per day, or 200 mg taken 5 times per day. Both of these dosages would typically be taken for 7 to 10 days. It usually takes around 2 to 6 weeks for the cold sore to heal. If you’re taking acyclovir preventatively, doctors may prescribe 400 mg taken 2 times per day.

You can help cold sores heal faster by using antiviral creams, keeping the area dry, avoiding touching the cold sore, and using sun protection.