Acyclovir
Indications
Acyclovir is an antiviral medicine used to treat infections caused by herpes viruses: cold sores and other herpes simplex infections of the skin and mouth, genital herpes (first episodes, recurrences and prevention of frequent outbreaks), chickenpox and shingles. It is also used to prevent herpes infections in people with weak immunity. It comes as tablets, suspension, cream, eye ointment and injection.
How It Works
It stops herpes viruses from copying themselves, which shortens the outbreak and eases symptoms. It does not remove the virus from the body, so outbreaks can come back.
Dosage and Administration
- Cold sores and herpes simplex (adults): usually 200 mg five times a day for 5 days; first genital herpes episodes may need 5 to 10 days.
- Prevention of frequent genital herpes outbreaks: usually 400 mg twice a day, as prescribed.
- Shingles and chickenpox (adults): usually 800 mg five times a day for 7 days.
- Cream: apply thinly to the sore five times a day for 5 days, starting at the first tingle.
- Children, people with kidney problems, eye ointment and injection (given by a doctor or nurse in hospital): as prescribed.
Start as early as possible, ideally within 72 hours of the shingles rash or at the first sign of a cold sore. Drink plenty of water. Finish the full course.
Interactions
Probenecid and Cimetidine can raise its level. Medicines that can affect the kidneys, such as Ciclosporin and Tacrolimus, need care, as do Mycophenolate and Theophylline. Tell the doctor about all medicines you take.
Contraindications
- Allergy to acyclovir, Valacyclovir or any ingredient of the product.
Side Effects
Common: nausea, vomiting, diarrhoea, stomach pain, headache, tiredness, itching and rash. Cream can cause brief burning, stinging or dryness.
Get urgent medical help if you have: confusion, agitation, hallucinations, shaking or fits (more likely in older people and those with kidney problems); passing much less urine or pain in the side; yellowing of the skin or eyes; unusual bruising or bleeding; or swelling of the face, lips or throat or difficulty breathing.
Pregnancy and Lactation
It has been widely used in pregnancy without clear harm, but use it only if the doctor advises. It passes into breast milk in small amounts and is generally considered compatible with breastfeeding; ask your doctor. Genital herpes near the time of delivery needs medical advice.
Precautions and Warnings
Tell the doctor if you have kidney disease, are elderly or are dehydrated, as the dose may need lowering. Genital herpes can spread even without sores; avoid sexual contact during outbreaks and use condoms. Keep the cream away from the eyes. Avoid touching cold sores and wash your hands after applying cream.
Overdose
Overdose can cause kidney problems, confusion, agitation, drowsiness and fits. Seek emergency medical help; hospital treatment may be needed.
Therapeutic Class
Antiviral (nucleoside analogue).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Do not freeze the cream or suspension.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.
All brands of Acyclovir