Aciclovir
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† Applies to UK only.
Other Related Treatments
MEDICAL INFORMATION
Aciclovir Key Facts
Other Related Names or Treatments
Zovirax, Sitavig
About Aciclovir
Aciclovir is an antiviral drug used for the treatment of cold sores (herpes labialis) and genital herpes (herpes simplex strain 2, HSV-2), which are both herpes viruses.
Aciclovir is also used to treat varicella zoster virus (VZV, herpes zoster), which causes chickenpox and shingles and is also used in immunocompromised patients to prevent infections such as cytomegalovirus (CMV) in those who have had an organ transplant.
Aciclovir’s mechanism of action is to block certain enzymes in the virus, preventing virus replication. This allows your immune system to control the infection.
NowPatient offers Aciclovir for the treatment of Herpes Simplex virus, genital herpes, and shingles only, following an online consultation with a prescribing clinician.
Key facts of Aciclovir
- Aciclovir is used to treat genital herpes, cold sores, and shingles (herpes zoster) in adults
- Aciclovir has some common side effects which include skin reactions, nausea and vomiting
- It can be dangerous if you take Aciclovir with certain medications. If you’re not sure if it is safe, discuss this with the prescribing clinician
Who is Aciclovir suitable for?
Aciclovir is suitable for adults between 18 and 65 years of age.
Who is Aciclovir not suitable for?
Aciclovir may not be suitable for some people. To make sure it’s safe for you, speak to the prescribing clinician before using Aciclovir if you:
- Have had an allergic reaction to the active ingredient Aciclovir in the past
- Have kidney disease
- Have liver problems
- Are over 65 years of age
- Have a weak immune system
How and where to get Aciclovir?
You can buy Aciclovir safely and securely from NowPatient. You can start a consultation today for free and if you qualify for treatment, you only pay for the cost of the medication. Delivery is made to your home or office from our registered pharmacy.
Our service is certified, safe and effective, and we only ever treat conditions. If you book a consultation with a prescribing clinician for the treatment of Herpes Simplex virus, genital herpes, or shingles, you can discuss if Aciclovir is a suitable treatment option for you.
At the end of the consultation, the clinician will decide if a treatment plan is suitable for you. If it is, the clinician will issue you with a prescription which can then be ordered, paid for and delivered directly to your chosen address by NowPatient.
Dosage and strength for Aciclovir for Herpes Simplex virus, genital herpes, and shingles
Aciclovir is available as a tablet, and when used for Herpes Simplex virus, genital herpes, or shingles, it is available in strengths ranging from 200 to 800 mg tablets.
Information about how to take Aciclovir for Herpes Simplex virus, genital herpes, and shingles
Your dose of Aciclovir will depend on the condition you are being treated for:
- Herpes Simplex virus – 200mg, five times a day for 5 days at 4 hourly intervals
- Genital herpes – 200mg, five times a day or 400mg three times a day for 5 days or longer if new lesion appear or healing incomplete
- Shingles – 800mg five times a day for 7 days at 4 hourly intervals
If you forget to take a dose, take it as soon as you can. If it is almost time for your next dose, skip the missed dose and take your next dose at your usual time. You should always complete the course of treatment as prescribed by your healthcare provider and read the patient information leaflet provided with your medication for further drug information.
What happens if you take too much Aciclovir?
If you take more than prescribed, then it can lead to some unpleasant side effects. You should talk to your doctor or reach out to one of our prescribing clinicians, if you have taken too much Aciclovir and you experience any of the following side effects:
What are the side effects of Aciclovir?
Very common side effects include:
- Headache
- Nausea
- Dizziness
- Vomiting
- Constipation
- Diarrhoea
- Abdominal pain
- Lower back pain
- Photosensitivity
- Skin rash
- Itching
If you experience any serious side effects, you should contact NHS 111.
If you experience a serious allergic reaction such as anaphylaxis with the signs shown below you should contact emergency services on 999.
- Your lips, mouth, throat or tongue suddenly become swollen
- You’re breathing very fast or struggling to breathe (you may become very wheezy or feel like you’re choking or gasping for air)
- Your throat feels tight or you’re struggling to swallow
- Your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
- You suddenly become very confused, drowsy or dizzy
- Someone faints and cannot be woken up
Always report adverse effects to the MHRA yellow card reporting system. You can read more about this here How and where do I report side effects of my medication? – NowPatient
Information about taking Aciclovir at the same time as other medications or herbal supplements
There is not enough evidence to suggest there are any drug interactions between herbal supplements and Aciclovir. In any event, you should let your prescribing clinician know if you are taking any herbal supplements.
Also, speak to your doctor if you are taking certain prescription drugs, in case of drug interactions:
- Aminoglycosides
- Methotrexate
- Cyclosporin
- Tacrolimus
- Cimetidine
- Probenecid
Can Aciclovir taken for Herpes Simplex virus, genital herpes, shingles be taken long term?
Courses of treatment of Aciclovir range from 5 to 7 days. If your condition has not improved within this time, speak to your doctor for medical advice.
Is there a herbal Aciclovir?
No. Herbal Aciclovir does not exist. If you have been marketed such a formulation, it may be fake.
Can women use Aciclovir?
Women can take Aciclovir for the treatment of Herpes Simplex virus, genital herpes, or shingles. However, Aciclovir is not recommended during pregnancy or if you are breastfeeding as Aciclovir may pass into breast milk. Checking with your doctor before taking Aciclovir.
Should I avoid any particular food or drink when taking Aciclovir?
You can eat and drink normally when taking Aciclovir for the treatment of Herpes Simplex virus, genital herpes, or shingles.
What lifestyle changes can I make to help me with Herpes Simplex virus, genital herpes, or shingles.?
Condoms can reduce the risk of getting genital herpes if used correctly, but be aware, a condom will only protect the area of the body it covers. You should also avoid sex while you have outbreaks of sores or blisters.
Shingles develops when the varicella-zoster virus, which originally caused chickenpox, is reactivated in your body, after you have already had chickenpox. There are vaccines such as Shingrix that are now available. Speak to your doctor for advice if you are considering the Shingrix vaccine.
Alternatives to Aciclovir
Alternatives for the treatment of Herpes Simplex virus, genital herpes, or shingles include other antiviral drugs such as Valtrex, valaciclovir, Famvir, or famciclovir.
Sources
Medical Disclaimer
NowPatient has taken all reasonable steps to ensure that all material is factually accurate, complete, and current. However, the knowledge and experience of a qualified healthcare professional should always be sought after instead of using the information on this page. Before taking any drug, you should always speak to your doctor or another qualified healthcare provider.
The information provided here about medications is subject to change and is not meant to include all uses, precautions, warnings, directions, drug interactions, allergic reactions, or negative effects. The absence of warnings or other information for a particular medication does not imply that the medication or medication combination is appropriate for all patients or for all possible purposes.
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FAQs
Answers to Popular Questions About Aciclovir
What is Aciclovir?
Aciclovir (also spelled aciclovir in the UK) is an antiviral medication used to treat and prevent infections caused by herpes simplex virus (HSV types 1 and 2) and varicella-zoster virus (VZV). It was one of the first effective antivirals and remains widely used. Aciclovir is available as tablets (200 mg, 400 mg, 800 mg), oral suspension, cream (5%), eye ointment (3%), and intravenous infusion. The oral tablets and cream are the most commonly prescribed forms in UK general practice.
What is Aciclovir used for?
Aciclovir is used to treat genital herpes (initial and recurrent episodes), cold sores (herpes labialis), chickenpox (varicella), shingles (herpes zoster), herpes simplex encephalitis (intravenous), and herpes eye infections (as eye ointment). It is also used for suppressive therapy to reduce recurrent genital herpes outbreaks. Aciclovir cream is available over the counter for cold sores.
How does Aciclovir work?
Aciclovir is a guanosine nucleoside analogue that selectively targets virus-infected cells. It is first activated by viral thymidine kinase, an enzyme found only in herpes-infected cells, and then further phosphorylated by cellular enzymes. The active form, aciclovir triphosphate, inhibits viral DNA polymerase and is incorporated into the viral DNA chain, causing premature chain termination. This selectivity means aciclovir has minimal effect on uninfected human cells, contributing to its excellent safety profile.
What is the usual dose of Aciclovir?
Dosing depends on the condition. For initial genital herpes: 200 mg five times daily for 5 days. For recurrent genital herpes: 200 mg five times daily for 5 days. For suppression: 400 mg twice daily, reviewed every 6–12 months. For shingles: 800 mg five times daily for 7 days. For chickenpox: 800 mg five times daily for 7 days. The five-times-daily regimen can be inconvenient, which is why many prescribers prefer valaciclovir (which offers twice-daily dosing with equivalent efficacy). Aciclovir can be taken with or without food.
Can I buy Aciclovir cream without a prescription?
Yes, aciclovir 5% cream (branded as Zovirax Cold Sore Cream or generic equivalents) is available over the counter from pharmacies for the treatment of cold sores. The cream should be applied five times daily at the first sign of tingling. Oral aciclovir tablets require a prescription. For frequent cold sore outbreaks, oral antiviral treatment may be more effective than the cream alone.
What are the side effects of Aciclovir?
Oral aciclovir is very well-tolerated. Common side effects include nausea, vomiting, diarrhoea, and abdominal pain. Headache and dizziness are reported occasionally. Skin rash and photosensitivity are uncommon. At high doses or in patients with renal impairment, aciclovir crystals can precipitate in the kidneys, so adequate hydration is important. Very rarely, neurological side effects (confusion, tremor, hallucinations) can occur, primarily in elderly patients or those with kidney problems. Aciclovir cream may cause mild stinging or dryness at the application site.
Is Aciclovir safe for long-term use?
Yes, aciclovir has been used for long-term suppressive therapy (years) with an excellent safety record. It is one of the most extensively studied antiviral medications. Long-term use does not appear to cause organ damage or cumulative toxicity. Your prescriber should review the need for continued suppression every 6–12 months. Adequate hydration and monitoring of kidney function are advisable for long-term use, particularly in older patients.
Is Aciclovir safe during pregnancy?
Yes, aciclovir has extensive safety data in pregnancy. The Aciclovir in Pregnancy Registry (over 1,000 exposures) showed no increase in birth defects. UK guidelines (BASHH, RCOG) recommend aciclovir for treating genital herpes in pregnancy and for suppressive therapy from 36 weeks’ gestation to reduce the risk of neonatal herpes. Aciclovir is considered compatible with breastfeeding — it is excreted in breast milk but in very low quantities that are unlikely to affect the infant.
How can I get Aciclovir?
Aciclovir cream is available over the counter from pharmacies for cold sores. Oral aciclovir tablets require a prescription from your GP, GUM clinic, or online prescribing service like NowPatient. Generic aciclovir is widely available and inexpensive. NowPatient provides convenient online consultations and discreet home delivery.
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