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Aciclovir
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Aciclovir is a highly effective antiviral medication used to treat outbreaks of genital herpes and cold sores by reducing the severity of the herpes simplex virus (HSV) through its active ingredient, aciclovir 400mg.
- Proven antiviral action that stops the herpes virus from replicating
- Reduces healing time and manages painful symptoms
- Available in convenient tablets for effective treatment
- Suitable for both acute flare-ups and long-term therapy
More information
You can buy aciclovir online safely through Mail my Meds by completing a brief clinical consultation which is reviewed by our UK-registered prescribers. If your consultation is approved, your medication will be dispensed and shipped directly from our registered pharmacy (GPHC Number: 9011560) in discreet, plain packaging to ensure your privacy.
Our pricing for aciclovir is competitive and transparent, ensuring you receive affordable care for your sexual health needs. Prices vary depending on the strength and the length of the course required, with further savings available for larger quantities intended for long-term suppression therapy.
We provide a range of delivery options to suit your schedule, including next-day delivery for urgent treatment of a sudden outbreak. All orders are sent in discreet packaging, so no one will know the contents of your delivery, maintaining total confidentiality throughout the process.
Aciclovir is an antiviral medicine used to treat infections caused by the herpes simplex virus (HSV), including genital herpes and cold sores. It is also effective against the varicella-zoster virus, which is responsible for chickenpox and shingles. In the UK, it is one of the most frequently prescribed treatments for managing recurrent outbreaks, helping to reduce the 3.5% increase in genital herpes diagnoses recently noted in national health reports.
The active ingredient in this medication is aciclovir, a synthetic nucleoside analogue that mimics the building blocks of DNA. Each tablet contains either 200mg, 400mg, or 800mg of the drug, alongside inactive ingredients that help the tablet dissolve and be absorbed by your system effectively.
Patients typically report that aciclovir works best when taken as soon as the "prodromal" phase begins—the period of tingling or itching before a blister appears. Most users find that their symptoms begin to improve within 1 to 2 days of starting the course, leading to a much faster recovery compared to using no treatment at all.
Every order of aciclovir includes a comprehensive Patient Information Leaflet (PIL) which provides detailed data on usage, safety, and storage. We highly recommend reading this leaflet before starting your treatment to ensure you are fully informed about your medication.
Aciclovir works by blocking the ability of the herpes virus to replicate its DNA, which prevents the infection from spreading to new cells. Once it enters an infected cell, the virus's own enzymes convert the drug into its active form, making it a "targeted" treatment that primarily affects cells where the virus is active, thus minimising damage to healthy tissue.
You should take aciclovir tablets whole with a glass of water, and it is vital to stay well-hydrated throughout your course to protect your kidney function. The tablets can be taken with or without food, but if you find they make you feel slightly sick, taking them after a meal may help settle your stomach.
The standard dosage for a genital herpes outbreak is usually 400mg taken three times a day for five days. Your specific dose may vary based on your medical history and whether you are treating an active infection or taking the medication daily for suppression.
| Condition | Typical Dosage | Duration |
|---|---|---|
| Genital Herpes Outbreak | 400mg three times daily | 5 days |
| Cold Sore (Oral) | 400mg three times daily | 5 days |
| Suppression (Prevention) | 400mg twice daily | Up to 12 months |
Common side effects of aciclovir include headaches, dizziness, and feeling or being sick, though these are usually mild and temporary. More serious side effects, such as an allergic reaction or kidney issues, are rare. However, if you experience significant swelling or a reduction in how much you urinate, you should seek medical attention immediately.
Before taking aciclovir, you must inform your prescriber if you have any pre-existing kidney problems or a weakened immune system. It is also important to note that while aciclovir treats the symptoms, it does not "cure" the virus, and you can still transmit herpes to others even while taking the medication. Avoiding sexual contact during an active outbreak is advised.
Aciclovir is often the first-line choice because it is cost-effective and highly reliable, though it requires more frequent dosing than its alternative, Valaciclovir. While Valaciclovir is a "prodrug" that converts into aciclovir in the body and only needs to be taken twice a day, aciclovir remains the gold standard for many patients due to its long-standing safety profile and lower price point.
Can you drink alcohol on aciclovir?
Yes, there are no known direct interactions between alcohol and aciclovir, but it is best to drink in moderation. Heavy drinking can dehydrate you and strain your kidneys, which are also responsible for processing the medication, potentially increasing the risk of side effects like headaches or dizziness.
Is aciclovir an antibiotic?
No, aciclovir is an antiviral medication, not an antibiotic. Antibiotics are only effective against bacteria, whereas aciclovir is specifically designed to target viruses like herpes simplex and varicella-zoster.
Does aciclovir work for cold sores?
Yes, aciclovir tablets are highly effective for treating cold sores, especially for people who suffer from severe or frequent outbreaks. While over-the-counter creams are available, oral tablets work systemically to tackle the virus from the inside, often providing more robust results.
Can I buy aciclovir over the counter?
In the UK, aciclovir cream for cold sores can be bought over the counter, but aciclovir tablets are prescription-only medicines (POM). You must have a consultation with a registered healthcare professional to ensure the treatment is safe and appropriate for you.
The information provided on this page is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or a qualified healthcare provider with any questions you may have regarding a medical condition.
Our clinical content is regularly reviewed by our team of UK medical experts and registered pharmacists to ensure all information is up-to-date, accurate, and aligned with current BNF and NICE guidelines.

