treatment icon

Acyclovir tablets

Dr Karen Martin
Reviewed by Dr Karen MartinReviewed on 19.10.2023 | 3 minutes read

Acyclovir is a prescription-only antiviral medicine that treats cold sores, shingles, chickenpox, and genital herpes. It does not cure a viral infection but helps reduce the outbreak's severity and length. In people with frequent outbreaks and those with a weak immune system, acyclovir tablets can be used to help reduce the number of future outbreaks as a preventative medication.

Acyclovir tablets can be used in children and adults. There are different dosages for taking these tablets depending on the patient, their medical history, and the type and severity of viral infection.

Doctor’s advice

Conditions it is used for

Shingles, caused by a type of herpes virus (herpes zoster), is an infection that causes a painful rash with shooting pain on only one side of the body. Usually, the rash appears as blotches on the chest and stomach but can appear in any area of the body, including the face, eyes, and genitals.

The same virus that causes genital herpes causes cold sores (herpes simplex virus or HSV) through a different strand (HSV-2). Speak to your doctor or visit your sexual health clinic as soon as possible if you notice painful blisters which burst to leave red open sores around your genitals (they can also exist on your anus, thighs, or bottom). Urinating can also be painful.

Chickenpox is caused by the varicella-zoster virus. It is common among children, but anyone can catch it at any age, but you can only catch it once. When adults get it, the symptoms are usually worse. Chickenpox spots begin as red spots all over the body. These red spots fill with fluid and are called blisters or vesicles. The blisters can burst and then eventually start to scab over. Chickenpox is often a very itchy disease that makes people quite uncomfortable. People may also feel quite poorly with fevers, poor appetite, and generalized aches and pains. Chickenpox usually lasts a few weeks. People are infectious from a couple of days before the spots appear until after the spots have all crusted over (usually about five days later).

Acyclovir tablets are not commonly used for cold sores, but there are some circumstances where your doctor will consider prescribing it. If they have, you should take your prescribed dose as soon as you recognize the tingling or burning sensation at the site of the outbreak. Cold sores are an infection caused by the herpes simplex virus – once you’ve had contact with the virus, it lies dormant in the nerves supplying the skin and may flare up from time to time. You might recognize triggers – stress, and exposure to the cold or sun are common ones. Unfortunately, acyclovir only treats the symptoms of a cold sore, nothing can cure you of the virus or prevent any future cold sores.

How does it work?

Acyclovir is an antiviral agent that interferes with the growth and replication of viral particles, helping your immune system to target and tackle the virus. 

Acyclovir is best used in the initial stages of an outbreak, usually within the first 5 days. For treatment of outbreaks, you will be taking a high dose for a short course, usually for 3-5 days. If you have a weakened immune system, treatment doses are usually double the standard doses for healthy individuals. Suppressive antiviral treatment is an option for frequent (usually around 6 or more per year) outbreaks that are causing distress or if outbreaks are affecting your social life.

Should anyone avoid taking it?

Do not take acyclovir tablets if you have previously experienced an allergic reaction to acyclovir or any ingredients (excipients) used to make acyclovir tablets.

Are there any side effects?

Acyclovir is generally well-tolerated in most individuals. A small number of patients may experience symptoms of fatigue, headache, feeling dizzy, nausea, vomiting, abdominal pain, itching, and a rash (including sensitivity to light). If these happen to you, stop taking the medication and seek advice from your doctor.

Was this helpful?

Was this helpful?

Dr Karen Martin
Reviewed by Dr Karen Martin
Reviewed on 19.10.2023
App Store
Google Play
Piff tick
Version 2.25.0
© 2024 Healthwords Ltd. All Rights Reserved