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Acyclovir (Aciclovir): uses, side effects & brands
Acyclovir treats cold sores, genital herpes, shingles and chickenpox. It belongs to the Antiviral group. Antivirals treat specific viral infections such as herpes, shingles or influenza.
Drug type — dosing is set by your doctor
| Measure | Range |
|---|---|
| Drug class | Antiviral |
| Type | Prescription |
| Dose | Individual — ask your doctor or pharmacist |
What it is used for
- Cold sores and genital herpes
- Shingles (herpes zoster)
- Chickenpox in some people
- Herpes eye infections (as eye ointment)
- Serious herpes infections such as encephalitis (by drip in hospital)
Common brand names
- India: Acivir, Zovirax, Ocuvir
- Worldwide: Zovirax
Common side effects
- Nausea, vomiting or diarrhoea
- Headache
- Mild stinging with the cream
Before taking it — precautions
- Drink plenty of water, especially if older or kidneys are weak
- Tell your doctor about kidney problems — the dose may need adjusting
- Pregnancy or breastfeeding — tell your doctor
When to see a doctor urgently
- Passing very little urine or swelling (kidney problem) (urgent)
- Confusion, hallucinations or shaking
- Severe allergy or blistering rash (urgent)
Frequently asked questions
Does acyclovir cure herpes?
No — it shortens and eases outbreaks but the virus stays in the body and can return.
When should I start it for shingles or cold sores?
As early as possible, ideally at the first tingle or within a few days of the rash, for the best effect.
Can it prevent outbreaks?
Yes, some people with frequent outbreaks take it regularly to reduce recurrences, as advised by a doctor.
Explore more
Sources & further reading
- World Health Organization (WHO)
- MedlinePlus — U.S. National Library of Medicine
- Ministry of Health & Family Welfare, India
- Indian Council of Medical Research (ICMR)
Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.