Aciclovir is a prescription-only antiviral medicine used to treat and prevent future outbreaks of cold sores caused by Herpes Simplex virus. Once you’ve had contact with the virus that causes cold sores, it lies dormant in the skin and may flare up from time to time. You might recognise triggers - stress and exposure to the cold or sun are common ones. There are available creams such as Zovirax that contain aciclovir and do not require a prescription, however aciclovir in tablet form does require a prescription.
Aciclovir helps to reduce the severity and length of an outbreak. In people with frequent outbreaks and in those who have a weak immune system, aciclovir tablets can be used to help reduce the number of future outbreaks as a preventative medicine. Aciclovir tablets are also used to treat outbreaks of the Herpes Simplex virus in other parts of the body. When treating cold sores with aciclovir tablets, you should take your prescribed dose as soon as you recognise the tingling or burning sensation at the site of the outbreak, ideally within 5 days.
Aciclovir is an antiviral agent that interferes with the growth and replication of viral particles, helping your immune system to target and tackle the virus. Prescribed treatment with aciclovir is best to be 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 5 days. If you are immunocompromised, treatment doses are usually double the standard doses for healthy individuals. Suppressive antiviral treatment is an option for frequent (6 or more) outbreaks causing distress or if outbreaks are affecting your social life.
Do not take aciclovir tablets if you have previously experienced an allergic reaction to aciclovir or any ingredients used to make aciclovir tablets.
Aciclovir 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).