Aciclovir

How to order Aciclovir

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3. Fill in a short health form.
4. A doctor reads your form.
5. If it is safe for you, they say yes.
6. Your order ships fast to your door.
7. It comes in a plain, sealed box.

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Aciclovir on Prescriptsy

Aciclovir is described on Prescriptsy as independent product information.

Here you can understand how online consultation works, what medical checks partner clinics carry out, and which factors matter when comparing providers.

We do not sell medicines directly, but help users compare licensed healthcare partners on price, delivery speed, service quality, and overall trustworthiness.

Important medical information

The information on this page does not replace a diagnosis or personalised advice from a doctor. Aciclovir is a prescription-only medicine (POM) that requires medical assessment before use.

It acts on viral replication and, like any medicine, carries a risk of side effects.

• Treatment with aciclovir should always be prescribed and supervised by a registered medical practitioner.
• If you develop signs of a severe allergic reaction, difficulty breathing, severe skin reaction, or symptoms suggestive of kidney problems, seek emergency medical attention immediately by calling 999.
• This page provides general information only. Always follow the instructions given by your doctor and read the Patient Information Leaflet supplied with your medicine.

What is aciclovir and how does it work?

Aciclovir is an antiviral medicine belonging to the nucleoside analogue class.

It is one of the most widely prescribed antivirals in the United Kingdom and has been in clinical use since the early 1980s.

Aciclovir is active against herpes simplex virus types 1 and 2 (HSV-1, HSV-2) and varicella-zoster virus (VZV), the virus responsible for chickenpox and shingles.

The drug works through a highly selective mechanism.

Once inside a cell infected with herpes virus, aciclovir is converted by a viral enzyme called thymidine kinase into its monophosphate form.

Cellular enzymes then convert it further into the active triphosphate.

This active form competes with natural building blocks of DNA and, when incorporated into the growing viral DNA chain, causes chain termination.

Because the initial activation step depends on a viral enzyme that is absent from uninfected cells, aciclovir acts preferentially on virus-infected cells and has relatively little effect on healthy tissue.

Aciclovir is available in the UK as tablets (200 mg and 800 mg), an oral suspension, an intravenous infusion (for hospital use), an eye ointment and a topical cream.

This page focuses on the systemic oral formulations. Topical aciclovir cream for cold sores is covered on a separate product page.

Licensed indications in the United Kingdom

Aciclovir tablets are licensed in the UK for several viral conditions. Your doctor will determine whether aciclovir is appropriate for your situation. The main licensed uses include the following.

Herpes simplex infections

Aciclovir is used for the treatment and suppression of herpes simplex virus infections.

This includes first episodes and recurrent episodes of genital herpes, as well as mucocutaneous herpes simplex in immunocompromised patients.

For a first episode of genital herpes, early treatment can significantly reduce the duration and severity of symptoms.

For patients who experience frequent recurrences, long-term suppressive therapy with aciclovir can reduce the number of outbreaks and the risk of asymptomatic viral shedding.

Herpes zoster (shingles)

Aciclovir at a higher dose is used to treat herpes zoster, commonly known as shingles. Treatment is most beneficial when started within 72 hours of rash onset.

In immunocompetent adults, oral aciclovir can reduce the duration of viral shedding, accelerate healing of lesions and reduce the severity of acute pain.

It may also reduce the risk of post-herpetic neuralgia, although evidence for this is mixed. In immunocompromised patients, intravenous aciclovir is often preferred.

Varicella (chickenpox)

Oral aciclovir is sometimes prescribed for chickenpox in adolescents, adults and immunocompromised patients, groups in which the disease tends to be more severe.

In otherwise healthy children, chickenpox is usually a self-limiting illness and antiviral treatment is not routinely recommended by NICE or the BNF unless there are risk factors for complications.

Who may be prescribed aciclovir?

Patients who may benefit

Your doctor may consider prescribing aciclovir if you have a confirmed or clinically suspected herpes simplex or varicella-zoster virus infection.

It is commonly prescribed in primary care for genital herpes, shingles in adults aged 50 and over or those with more severe presentations, and occasionally for chickenpox in adults.

Patients with weakened immune systems may receive aciclovir as prophylaxis to prevent reactivation of herpes viruses during periods of immunosuppression.

Patients who may not be suitable

Aciclovir may not be appropriate if you have a known allergy to aciclovir or valaciclovir, severe renal impairment without appropriate dose adjustment, or significant dehydration.

Your doctor will assess your kidney function and adjust the dose accordingly. Tell your doctor about all your medical conditions, particularly any kidney problems, before starting treatment.

How to take aciclovir tablets

Aciclovir tablets should be swallowed whole with a full glass of water.

It is important to drink plenty of fluids throughout the day while taking this medicine, as adequate hydration helps prevent the drug from crystallising in the kidneys.

You can take aciclovir with or without food.

The dosing schedule varies depending on the condition being treated.

For herpes simplex, the standard regimen involves taking tablets five times a day at roughly four-hourly intervals, missing out the overnight dose.

For shingles, the dose is higher and tablets are again taken five times daily. Your doctor or pharmacist will explain the exact schedule.

If you forget a dose, take it as soon as you remember.

If it is nearly time for the next dose, skip the missed one and continue as normal.

Do not take a double dose to make up for a forgotten one.

Complete the full course of treatment even if your symptoms improve before the tablets are finished.

Aciclovir and the NHS

Aciclovir is a well-established medicine within the NHS.

It is listed in the British National Formulary (BNF) and is recommended in NICE clinical guidance for the management of herpes simplex and herpes zoster infections.

Generic aciclovir tablets are widely available and relatively inexpensive, making them one of the most cost-effective antiviral treatments in the UK.

In England, a standard NHS prescription charge of nine pounds and ninety pence per item applies unless you are exempt.

Patients in Scotland, Wales and Northern Ireland do not pay prescription charges. If you require long-term suppressive treatment, a pre-payment certificate may reduce your costs.

Your pharmacist can advise on the options available.

Common side effects of aciclovir

Most people tolerate aciclovir well. The most commonly reported side effects include headache, nausea, vomiting, diarrhoea and abdominal discomfort.

Skin reactions such as rash and photosensitivity have also been reported. These effects are generally mild and tend to resolve once treatment is completed.

Less common side effects include dizziness, fatigue, elevated liver enzymes detected on blood tests, and mild increases in blood urea or creatinine levels. Reversible hair thinning has been reported in a small number of patients.

Serious side effects are rare but can include severe allergic reactions (anaphylaxis), acute kidney injury, hepatitis, and neurological symptoms such as confusion, hallucinations, tremor or convulsions.

Neurological effects are more likely in patients with impaired kidney function or when the drug is administered intravenously at high doses.

If you experience any of these symptoms, stop taking aciclovir and seek urgent medical attention.

Aciclovir versus valaciclovir

Valaciclovir is a prodrug of aciclovir, meaning it is converted into aciclovir in the body after absorption.

The main advantage of valaciclovir is improved oral bioavailability, which means that higher blood levels of aciclovir can be achieved with fewer daily doses.

While aciclovir for genital herpes is typically taken five times daily, valaciclovir is usually taken two or three times daily, which many patients find more convenient.

Both medicines are equally effective once converted to the active drug. The choice between them often comes down to dosing convenience, cost and individual patient preference.

Aciclovir tablets are generally less expensive, while valaciclovir may improve adherence because of its simpler dosing schedule.

Your doctor will help you decide which is most suitable for your circumstances.

Special considerations

Pregnancy and breastfeeding

Aciclovir has been used during pregnancy for many years and a large body of post-marketing data has not shown an increased risk of birth defects.

However, as with all medicines, it should only be used during pregnancy if the expected benefit to the mother justifies any potential risk to the baby.

Your doctor will discuss this with you and help weigh up the decision.

Aciclovir does pass into breast milk, but the amounts are generally considered too small to cause harm to a nursing infant.

Nevertheless, speak with your doctor before breastfeeding while taking this medicine.

Elderly patients

Older adults are more likely to have reduced kidney function, which affects how aciclovir is cleared from the body. Dose adjustments based on creatinine clearance are often necessary.

Elderly patients may also be more susceptible to neurological side effects such as confusion or drowsiness. Adequate hydration is particularly important in this group.

Immunocompromised patients

Patients with compromised immune systems, such as those living with HIV, organ transplant recipients or those receiving chemotherapy, may require longer courses, higher doses or intravenous formulations.

Prolonged use in immunocompromised individuals carries a risk of antiviral resistance, which should be monitored by a specialist. In some cases, alternative antivirals may be needed.

Storage, packaging and availability

Aciclovir tablets should be stored below 25 degrees Celsius in a dry place, away from direct sunlight.

Keep them in the original packaging and out of the reach of children. Do not use after the expiry date printed on the pack.

In the UK, aciclovir tablets are manufactured by several generic pharmaceutical companies and are widely available from community pharmacies.

The most common pack sizes are 25, 35 and 56 tablets, depending on the strength. Your pharmacist will dispense the quantity prescribed by your doctor.

Is aciclovir available without a prescription in the UK?

Aciclovir tablets are classified as a prescription-only medicine (POM) in the United Kingdom and cannot be obtained without a valid prescription from a registered prescriber such as a GP or an independent prescriber pharmacist.

Websites that claim to sell aciclovir tablets without a prescription are operating illegally, and medicines obtained through such channels may be counterfeit, contaminated or incorrectly dosed.

It is worth noting that aciclovir cream for cold sores can be purchased from pharmacies without a prescription in certain circumstances. However, this is a different formulation and is covered on a separate product page.

There are legitimate online services in the United Kingdom that provide aciclovir tablets following an online consultation with a GMC-registered doctor or GPhC-registered prescriber pharmacist.

These services issue genuine NHS or private prescriptions that are dispensed by licensed UK pharmacies.

If you are considering this route, make sure the service is registered with the Care Quality Commission (CQC) in England, Healthcare Inspectorate Wales (HIW), Healthcare Improvement Scotland (HIS) or the Regulation and Quality Improvement Authority (RQIA) in Northern Ireland.

When to seek medical advice

Contact your GP or call NHS 111 if your symptoms do not improve within a few days of starting treatment, if you develop new or worsening symptoms, or if you have concerns about side effects.

Seek emergency help by calling 999 if you experience signs of a severe allergic reaction such as swelling of the face, lips, tongue or throat, difficulty breathing, or a widespread blistering skin rash.

Prompt medical attention is also needed if you develop confusion, hallucinations or seizures, which may indicate neurological involvement.

Sources and further reading

• Summary of Product Characteristics, Aciclovir Tablets, EMC (medicines.org.uk)
• British National Formulary, Aciclovir, bnf.nice.org.uk
• NICE Clinical Knowledge Summaries, Herpes simplex, cks.nice.org.uk
• NICE Clinical Knowledge Summaries, Shingles, cks.nice.org.uk
• NHS, Aciclovir, nhs.uk
• MHRA Yellow Card Scheme, yellowcard.mhra.gov.uk