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Aciclovir

Genital Herpes|Active ingredient(s): Aciclovir|Manufacturer: Various

A woman’s face, close-up with a cold sore, holding up a pack of unnamed tablets.

Fast-acting and effective treatment to manage herpes

  • Treats outbreaks of cold sores and genital herpes.
  • Reduces outbreak time and relieves symptoms.
  • Treats the outbreak in 5 days.
  • Take one tablet 5 times a day.

How to take

A hand is grabbing an unbranded bottle of pills.

Action at the first sign of an outbreak

Taking Aciclovir as soon as you notice an outbreak significantly improves recovery time and reduces the duration of the outbreak.

A close-up of a calendar with the 5th date circled in a red pen.

Treats an outbreak in 5 days

You take the 200 mg Aciclovir 5 times a day for 5 days. This means you take it every 4 hours (e.g. 6 am, 10 am, 2 pm, 6 pm and 10 pm).

A close-up of a man’s hand stopping a potential virus.

Prevents future outbreaks

You can take the 400 mg dose of Aciclovir tablets for cold sores to help keep an outbreak at bay.

What others say about Aciclovir

Trustpilot review
58 reviews with score 4.9

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Prescription is included.

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UK: Free next-day delivery.
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Aciclovir

What is Aciclovir?

Aciclovir is an antiviral medicine that is used to manage conditions caused by the herpes virus (HSV). This includes genital herpes and cold sores. It is also sometimes used to treat shingles.

You can take Aciclovir tablets to both treat and prevent outbreaks of genital herpes and cold sores. It works by stopping the virus from growing and spreading, which controls the infection and helps to treat it.

It does not cure the herpes virus. Most people will live with herpes for the rest of their lives. But Aciclovir can help to treat an outbreak or prevent future outbreaks quickly.

How does Aciclovir work?

Aciclovir is a type of medicine called an antiviral medicine. It is a type of antiviral that specifically treats strains of the herpes virus (herpes simplex virus or HSV).

It works by stopping the DNA of the herpes virus, which helps to stop the virus from spreading and growing. This allows your immune system to fight the virus and treat the outbreak.

How effective is it?

Research shows Aciclovir tablets are an effective treatment for cold sores and genital herpes.

Cold sores

  • Research shows early treatment with Aciclovir significantly reduces the duration of pain and the duration of the outbreak.
  • Aciclovir tablets can reduce the duration of a cold sores outbreak by 1 day.

Genital herpes

  • 95% see complete treatment of sores after 5 days, 100% after 7 days.
  • Only 6 in 100 patients had a recurrence of symptoms in 84 days after Aciclovir treatment.

How long does it take Aciclovir to work?

Aciclovir significantly reduces the duration of an outbreak.

Aciclovir should treat genital herpes and cold sores outbreaks in 5 days in people with regular immune systems. Recurrent infections may take 3-5 days to treat.

An outbreak may take longer to treat if new sores appear or if you have a weakened immune system.

Who can use Aciclovir?

Most men and women aged 18 and over can use Aciclovir.

Some people should consult their doctor before using Aciclovir. This is because they may be at a higher risk of side effects. This includes people who:

  • are elderly
  • have kidney problems
  • are prone to dehydration
  • have liver disease
  • have abnormal levels of electrolytes (salts) in their blood
  • have severe breathing problems

Consult your doctor if you are unsure whether any of these conditions apply to you.

Can you take Aciclovir when pregnant?

Aciclovir is not known to be harmful during pregnancy. But your doctor will only prescribe it if they believe the benefits outweigh the potential risk.

What dose should I take?

The dose you need to take will depend on your situation.

Cold sores:

  • Treatment - take 200 mg 5 times a day for 5 days* (every 4 hours).
  • Prevention - take 400 mg twice daily.

Genital herpes:

  • Treatment (first episode) - 200 mg 5 times a day for 5 days* (every 4 hours).
  • Recurrent treatment - 200 mg 5 times a day for 5 days (every 4 hours).
  • Prevention - take 400 mg twice daily.

*You may require longer treatment if new sores appear.

Always follow the advice from your doctor.

Are there any side effects?

Like all prescription medicines, Aciclovir may cause side effects. The most common side effects should go away on their own once your body gets used to the medicine.

Common side effects (up to 1 in 10 people):

  • stomach pain
  • diarrhoea
  • dizziness
  • tiredness (fatigue)
  • fever
  • headache
  • feeling sick (nausea)
  • sensitivity to the sun
  • skin reactions
  • vomiting

Speak to your doctor as soon as possible if you experience any persistent or serious side effects.

For a full list of side effects, please refer to the patient information leaflet (PIL) which comes in the box with your medicine.

Can you drink on Aciclovir?

It is safe to drink alcohol whilst taking Aciclovir. However, if you are experiencing side effects such as dizziness or fatigue, alcohol may make you feel worse.

Is Aciclovir safe?

Yes, Aciclovir is a safe and clinically-proven treatment for herpes. But if you have another medical condition or take other medication, your doctor will need to ensure it’s safe for you. Our doctors will also know whether it’s safe for you based on your medical questionnaire during the ordering process.

Can I get Aciclovir without a prescription?

Aciclovir tablets are not available without a prescription. You need a valid prescription from a healthcare professional to purchase it. This ensures the medication is safe and suitable for your needs.

However, you can buy Aciclovir cream in the UK (known as Zovirax) without a prescription for cold sores.

Medical review byDr. Caroline FontanaLast review 07 November 2025
Dr. Caroline Fontana

Note: You must complete a short online consultation so that our doctor can ensure that the treatment is suitable for you. The above pricing should only be used as a reference. The final decision to issue this treatment lies with the prescribing doctor.

Aciclovir Overview

Type of medicine: Antiviral
Used for: Cold sores and genital herpes
Active ingredient: Aciclovir
Works by: Stopping the spread and growth of viral cells
Effective within: 5 days
Available as: Tablets
Available dosages: 200 mg & 400 mg
Usage instructions: Take one 200 mg tablet 5 times a day for 5 days (to treat cold sores or genital herpes)
Packaging: Cardboard carton containing foil blister packs of tablets
Branded available No

FAQs

What is included in the online consultation?
Will a doctor review my consultation?
What happens after I submit my order?
What services are included with my order?
Is the price all-inclusive?
What are my delivery options?
Is it safe to buy prescription medication online?
Is this service discreet?
What is included in the online consultation?

Our online consultations are in the format of short medical questionnaires. You will be asked general questions about your health and medical history, as well as specific medical questions relevant to the treatment you have chosen. We will also ask you for your payment and delivery details to complete the order.

Online consultations take no longer than 5 minutes to complete. All questions are necessary when issuing prescription medicines. It means that our doctors can make sure the treatment is safe and right for you.

Will a doctor review my consultation?

Yes, it is a legal requirement that all online consultations are reviewed by a registered doctor. This is to make sure the chosen treatment is safe and right for you to take. All personal information is stored securely and confidentially.

Please note, all orders are subject to doctor approval, and we cannot guarantee that your order will be approved.

What happens after I submit my order?

Your online consultation will be sent directly to our medical team, where it will be reviewed by on of our in-house doctors.

If a doctor approves you for treatment, they will issue a prescription. Your prescription will then be forwarded to our pharmacist, where you medication will be dispensed and dispatched for delivery.

What services are included with my order?

Every order includes:

  • Free consultation - your consultation will be personally reviewed by one of our registered doctors.
  • Free prescription - a doctor will issue you a prescription if approved for treatment.
  • Free delivery - we provide free express delivery across Europe, you should receive your order in 1-2 working days.
Is the price all-inclusive?

Yes, our service is all-inclusive and there are no hidden fees. All 121doc orders include a free online consultation, a free prescription and free express delivery.

What are my delivery options?

We offer several delivery options at no extra charge:

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All these options can be tracked and require a signature on delivery. If you are not in, a friend or relative can sign in your place.

Is it safe to buy prescription medication online?

It is safe to buy prescription medications online from genuine and reputable healthcare providers, like 121doc.

Our medical staff and facilities are registered with the relevant medical governing bodies. We also ensure your data is protected by adhering to European data privacy laws.

You can learn more about our certifications here.

Is this service discreet?

Our patients’ privacy is of utmost importance. All your medical information is securely stored and only viewed by our doctors. We do not share your details with third-parties. We are also closely adhere to data privacy laws.

All orders will only show on invoices, bank statements, etc. as ‘HHC Ltd’.

How does it work?

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As soon as you place the order, one of our doctors will review your consultation. On working days, this usually takes around one hour.

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If the doctor has any additional questions, you will receive a phone call and an email. We understand you might be at work or busy. Our customer service representatives are always discreet and can call back at a more convenient time if necessary.

Our emails never contain any personal or medical information, only a link to your private account on our website (where you will find your messages).

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Once our pharmacy receives your prescription, you will get a second email with your package tracking code.

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All orders include next-day delivery. Alternatively, you can select a delivery date that suits you better.

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We also provide a free UPS Access Point service. Pick up your package from one of many collection points across the UK.

With your tracking code, you will know the estimated delivery time. All we need is your signature (or a friend‘s or relative’s).

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All parcels are plainly labelled; there is no logo or any indication of its contents. Inside, you will find your treatment as well as a patient leaflet in your chosen language.

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With 121doc’s Subscribe & Save service, you can automatically receive your treatment every few weeks or months.

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