aciclovir genital herpes
  • aciclovir genital herpes

Aciclovir Tablets

Medication features

  • 400mg Tablets
  • Antiviral treatment for genital herpes
  • Outbreak or Suppression dosages
  • 5-day course


Aciclovir 400mg Tablets Online UK

You can request to buy Aciclovir tablets from our UK registered online pharmacy and doctor service. This service is for those who have been diagnosed with genital herpes previously and require herpes treatment or suppression.

No prescription is required, however, you will need to complete an online assessment, so our doctors can issue a prescription to our pharmacy. If the doctors approve your order, a prescription is passed to our pharmacy team, who will then dispense and dispatch your medication.

What is Aciclovir?

Aciclovir (Acyclovir) is an antiviral medication used to treat or suppress infections caused by the herpes simplex virus. The antiviral tablets prevent the virus from multiplying, allowing the immune system to effectively suppress the herpes infection over the course of treatment.

Aciclovir is also used in the treatment of other viral infections such as cold sores, chickenpox and shingles (varicella-zoster virus). Our service can prescribe Aciclovir tablets for genital herpes only, for other conditions, visit your GP.

Acyclovir is the same medicine but with a different spelling, usually used by people from the United States.

How does Aciclovir work?

Aciclovir tablets work by targeting the virus when it tries to multiply. It blocks the viruses ability to grow its DNA successfully preventing it from producing more of itself. This greatly reduces the viral load on the body, allowing the immune system to get the upper hand on the herpes infection, treating or suppressing it.

What is genital herpes?

Genital herpes is a viral infection that can cause blisters to appear on the genitals. These are often painful sores that come and go. They will often weep fluids that may infect others through skin to skin contact during sexual intercourse. It is a lifelong infection with no known cure.

Antiviral treatments can be effective at suppressing the infection when an outbreak occurs or preventing the majority of outbreaks however, it will not clear the condition completely from the body. As the infection can be passed to others when outbreaks occur, it is best to refrain from sex during this time and/ or always use barrier protection during intercourse.

Aciclovir 400mg dose

To treat genital herpes in adults, Aciclovir should be taken three times daily. It is important to drink plenty of fluids (preferably water) when taking a course of these antivirals to minimise potential side effects. 

If Aciclovir is being used to suppress an outbreak, the dosage is one tablet twice daily. Suppression treatment is used in people who have frequently recurring outbreaks of herpes. This is generally defined as more than 6 outbreaks per year.

The prophylactic treatment can help reduce, or completely stop recurring outbreaks. In addition, future outbreaks generally don't last as long and are less aggressive.

Aciclovir 400mg Summary


Take ONE tablet THREE times daily for 5 days

Type of medicine

Antiviral Tablet


Stops viral DNA replication, stopping it from multiplying

Available Sizes

15-168 Tablets

Active Ingredient

Aciclovir 400mg


From £9.95 (includes script and medicine)

Side Effects

Can include headaches, nausea, stomach upset, sensitivity to sunlight

Aciclovir 400mg Prices

15 Tablets (1 outbreak)


30 Tablets (2 outbreaks)


45 Tablets (3 outbreaks)


168 Tablets (Suppression course)


Comparing treatments

All of the main treatments for genital herpes are anti-virals which work in the same way. The main point of difference is that while Aciclovir needs to be taken three times daily, Valaciclovir and Famciclovir require twice-daily dosage. This makes taking the other treatments slightly easier for those who may struggle to remember the midday dose of Aciclovir.

Aciclovir is, however, the most cost-effective option, as both of the other antivirals are more expensive. You can find a detailed comparison of Aciclovir tablets and cream here.

Aciclovir Side Effects

As with all medicines, aciclovir does have the potential to cause some side effects, although not everyone will experience them. The Common side effects of Aciclovir tablets are stomach pain, diarrhoea, fatigue, headaches, nausea, sensitivity to light and itching.

For information on rare side effects (1 in 1,000 to 1 in 10,000), read the patient information leaflet.

If you experience any severe side effects or symptoms of an allergic reaction (breathing difficulties, itching, hives, rash) you should seek immediate medical attention. If you experience any prolonged side effects you should speak to the prescribing doctor.


Tyson Wilkman, Clinical Pharmacist


Tyson Wilkman

RoleClinical Pharmacist
Qual.Bachelor of Pharmacy (Honours)
AboutTyson started with Simple Online Pharmacy in 2021. He's responsible for helping author and review accurate site content. He works with our GPs to make sure all aspects of the medicines are covered.


What are Aciclovir tablets for?

Aciclovir tablets can be used for viral infections such as cold sores, genital herpes, chickenpox and shingles. Each may require different doses and duration of treatment. Follow your doctor's directions.

Can I buy Aciclovir tablets over the counter in the UK?

No, Aciclovir is a prescription-only medicine in the UK. You may request Aciclovir 400mg tablets online from a registered UK doctor and pharmacy service after an online consultation.

Where can I buy Aciclovir tablets in the UK?

You can buy Aciclovir tablets from any UK pharmacy with a prescription from a UK registered doctor. You may request a prescription online from a registered online doctor and pharmacy who can have a UK doctor review your request and provide treatment delivered through the Royal Mail service.

How long is a course of Aciclovir tablets?

This will depend on the virus your doctor has prescribed the treatment for. Genital herpes treatment is generally one tablet three times a day with a glass of water or one tablet twice a day for suppression therapy.

Is Aciclovir cream available?

Yes, Aciclovir cream is available to treat cold sores. It contains 5% Aciclovir and is available in a 2g or 5g tube. You can find a detailed comparison between Aciclovir tablets and cream here.

What strength are Aciclovir tablets?

Aciclovir comes in a variety of strengths. The strength you get prescribed by your doctor will depend on what condition is being treated. It can come in Aciclovir 200mg, 400mg and 800mg.


Treatment Comparison

Outbreak DosageOne tablet THREE times daily for five daysOne tablet TWICE daily for 5 daysOne tablet TWICE daily for 5 days
Suppression DosageOne tablet TWICE daily for 3 months One tablet TWICE daily for 3 monthsOne tablet TWICE daily for 3 months
MechanismPrevents the virus from multiplyingPrevents the virus from multiplyingPrevents the virus from multiplying
PriceCheapest. From 9.95.More expensive. From £22.95.More expensive. From £19.95.


Info Leaflet

Before taking any medication, it is important to read the patient information leaflet.


Warnings & Precautions

Aciclovir may not be suitable for all people. If you have ever experienced any allergic reactions to antiviral medicines or any listed ingredient of aciclovir, do not take the medicine and consult your doctor for your options.

Those with the following should speak to the doctor in depth about suitability before using the medicine. Those with:

  • Kidney problems
  • An age over 65
  • Nervous system abnormalities
  • A tendency to become dehydrated often

Other medicines

There are some medicines that may interact with Aciclovir treatment or result in potentially more side effects. It is important that you provide a complete list of your medicines for our doctor when completing your online consultation. In particular cimetidine, probenecid, mycophenolate mofetil and theophylline have notable interactions.

Other medical conditions

Conditions that affect the kidneys and general kidney problems may make you unsuitable for antiviral treatments.

Aciclovir in Pregnancy and Breastfeeding

Aciclovir can be used during pregnancy and breastfeeding although it is generally not recommended without consulting your doctor. There must be an individual risk-benefit assessment to determine if viral suppression therapy is needed.

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Aciclovir Tablets

Medication Simple Online Pharmacy
400mg x 15 - 1 Outbreak £9.95
400mg x 30 - 2 Outbreaks £15.95
400mg x 45 - 3 Outbreaks £23.95
400mg x 168 - Suppression Course £31.95


Medication Simple Online Pharmacy
1 Outbreak - 10 Tablets £14.95
2 Outbreaks - 20 Tablets £19.95
3 Outbreaks - 30 Tablets £23.95
Supression Course - 84 Tablets £34.95

Valaciclovir 500mg

Medication Simple Online Pharmacy
500mg x 10 - 1 Outbreak £22.95
500mg x 20 - 2 Outbreaks £43.99
500mg x 30 - 3 Outbreaks £59.99
500mg x 84 - Supression Course £139.99
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