Acyclovir: Uses, How It Works, Medicines
Acyclovir (aciclovir) is a prescription antiviral used to treat infections caused by herpes viruses. These include cold sores, genital herpes, shingles and chickenpox. It slows the virus but does not remove it from the body, and it works best when started early. It belongs to the antivirals.
Also known as: Aciclovir, Acyclovir tablet, Acyclovir 400 mg, Zovirax, Acivir
Pharmacist review in progress. This page is based on the sources listed below and is being checked by our registered pharmacist.
How does Acyclovir work?
Acyclovir is changed inside virus-infected cells into a form that the virus mistakes for one of its building blocks. This stops the virus copying its genetic material. The virus spreads less, but it stays in the body.
How to take Acyclovir
Follow the label or your doctor's advice. Acyclovir is usually taken several times a day for a number of days, with plenty of water. Your doctor decides the dose and how long you need it.
Side effects of Acyclovir
Most people take acyclovir without serious problems. Some side effects are common and mild, but a few need medical help.
Uncommon or mild
- Headache or dizziness
- Nausea, vomiting, diarrhoea or stomach ache
- Skin rash or itching, or a skin reaction in sunlight
- Tiredness or a high temperature
Rare but serious: get medical help
- Swelling of the face, lips, tongue or throat, or difficulty breathing (a severe allergic reaction). Get medical help immediately
- Yellow skin or eyes (possible liver problems)
- Passing much less urine than usual (possible kidney problems)
- Confusion, agitation or seizures
Who should be careful
Some people need to check with a doctor before taking acyclovir, or need extra care while taking it.
When the label says not to use it
- Allergy to acyclovir, valaciclovir or any ingredient of the tablet
- Allergy to acyclovir or valaciclovir
- Kidney problems: the dose may need to change
- Dehydration from vomiting or diarrhoea: drink plenty of fluids
- Weakened immune system, such as HIV or chemotherapy
- Pregnancy and breastfeeding: tell your doctor before taking it
- Genital herpes can still spread to a partner when there are no visible sores
Medicines and things that interact with Acyclovir
Acyclovir can interact with some other medicines. Tell your doctor or pharmacist about everything you take, including herbal remedies.
- Probenecid (a gout medicine)
- Cimetidine (a stomach acid medicine)
- Mycophenolate mofetil (used after an organ transplant)
If someone takes too much
One extra tablet by mistake is unlikely to cause problems, but larger amounts can harm the kidneys. If someone has taken much more than prescribed, call 112 or go to the nearest hospital.
Regulatory status in India
Approved for sale in India as a prescription medicine. Single-ingredient acyclovir is not on the CDSCO list of medicines banned under section 26A of the Drugs and Cosmetics Act. Check the schedule printed on the pack.
Type of medicine
Acyclovir belongs to this type of medicine.
Medicines that contain Acyclovir
These medicines sold in India contain Acyclovir. They are listed A to Z, not ranked.
- Acivir 400 · 400 mg tablet
What is Acyclovir used for?
Medicines that contain Acyclovir are used for these conditions.
Other medicines of the same type
These active ingredients are of the same type as Acyclovir.
Common questions
What is acyclovir used for?
Acyclovir is an antiviral used on a doctor's advice for infections caused by herpes viruses, such as cold sores, genital herpes, shingles and chickenpox. It slows the virus but does not remove it from the body.
Does acyclovir remove the herpes virus for good?
No. It slows the virus so the infection can settle sooner, but the virus stays in the body and can return. Ask your doctor what to expect and how to avoid passing genital herpes to a partner.
Why drink plenty of water with acyclovir?
Acyclovir leaves the body through the kidneys. Drinking enough fluid helps the kidneys clear it, which matters more if kidney function is reduced or you are vomiting or have diarrhoea. Tell your doctor if you cannot drink enough.
Sources
- Aciclovir. NHS (UK)
- Acyclovir. MedlinePlus, US National Library of Medicine
- Shingles. NHS (UK)
- ATC/DDD Index: J05AB01. WHO Collaborating Centre for Drug Statistics Methodology
- List of drugs prohibited for manufacture and sale through gazette notifications under section 26A of the Drugs & Cosmetics Act 1940. Central Drugs Standard Control Organisation (CDSCO)