Aciclovir is an antiviral medicine which means it is designed to act against viruses. Aciclovir is specifically designed to treat the herpes simplex virus that causes cold sore symptoms, as well as some other closely related viruses, such as the virus that causes chicken pox and shingles.
Aciclovir works by interrupting the normal process of viral replication – when viruses copy themselves inside your cells. This helps reduce the number of viruses in your body and in turn helps reduce the severity of symptoms experienced. Since the virus reproduces very early in the infection, you will benefit most from treatment if you take Aciclovir Tablets as soon as the first symptoms appear, ideally within 5 days of their appearance.
This medication does not cure cold sores as the virus continues to live in the body even after an outbreak, but it works to reduce the severity and length of the outbreak whilst decreasing the risk of transmitting the virus to other people. Aciclovir starts working almost immediately after you start taking it and is effective in reducing the healing time and reducing the risk transmitted to other people.
Aciclovir is an oral medication which comes in a 400mg tablet formulation. It is swallowed with water three times a day for 5 days with or without food. The treatment is most effective when you use it at the first signs of cold sore symptoms (i.e. visible blisters and a burning sensation). It is important to remain hydrated during the course of your treatment to minimise the risk of dehydration. Whilst alcohol is not prohibited whilst taking this medication, it is important to limit consumption to allow the medication to work properly.
How quick and well Aciclovir works will depend on the severity of your symptoms and how soon you notice the symptoms before starting treatment. As soon as you start to notice the symptoms, it is best to start taking Aciclovir.
Aciclovir is usually more cost effective but it has to be taken more frequently than Valaciclovir making the latter more convenient to fit into a patient’s daily lifestyle.
Always use this medication exactly as your clinician has told you. Check with our clinical team or your GP or pharmacist if you are not sure.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
The following are common side effects of Aciclovir:
- Headaches
- Dizziness
- Nausea or vomiting
- Abdominal pain
- Diarrhea
- Itching or an itchy rash
- Skin is sensitive to sunlight
- Tiredness
- Fever
If you have a fever it’s always important to contact a doctor to check for any other underlying causes for this.
For full information on side effects and correct use, see the patient information leaflet. If any side effects concern you, or you are experiencing any of the side effects mentioned in the patient information leaflet whilst taking this medication, please contact our clinical team or speak to your GP.
If you have a damaged or weakened immune system (immunocompromised) you should seek medical advice before taking Aciclovir and at any time you experience a cold sore or other infection.
If you are elderly, renally impaired, pregnant or breastfeeding, you should seek medical advice before taking aciclovir.
Get emergency medical help if you have signs of an allergic reaction to this medication. These include:
- Hives
- Dizziness
- Fast or pounding heartbeats
- Wheezing
- Difficult breathing
- Swelling of your face, lips, tongue, or throat.
It is important that you let us know which prescription, over-the-counter medicines and recreational drugs you are currently taking. You must also tell us about any other medical conditions that you currently have (or had in the past). This will help us ensure the prescribed medication is safe and appropriate for you to take.
For full information on warnings, medication interactions and contraindications, refer to the Patient Information Leaflet. Please read all packaging and the Patient Information Leaflet before taking any new medicine and inform our clinical team or your GP of medicines you are taking or intend to take.
