Aciclovir for Shingles

Aciclovir is an antiviral medicine used to treat shingles (herpes zoster), which is caused by reactivation of the varicella-zoster virus. It works by blocking the virus from copying its DNA, which helps to reduce the severity and duration of your rash and lowers the risk of complications like lasting nerve pain.

Antiviral treatment for shingles works best when started within 72 hours of your rash first appearing. Starting this early gives the best chance of reducing how severe and how long your symptoms last. A prescriber may still consider treatment slightly later than this if you're still developing new blisters.

For shingles, aciclovir is prescribed at a higher dose than for cold sores or genital herpes: 800mg, taken five times a day, for 7 to 10 days. Your prescriber will confirm the exact dose and course length for you based on your consultation.

The most commonly reported side effects include nausea, vomiting, diarrhoea, stomach pain, headache, dizziness, and tiredness. These are usually mild. Seek urgent medical help if you notice signs of a serious allergic reaction, such as facial swelling, difficulty breathing, or a severe rash.

You can't catch shingles from someone else if you've already had chickenpox or been vaccinated against it. However, the fluid inside the blisters can trigger chickenpox in someone who hasn't had it. Until your rash has fully crusted over, it's best to avoid close contact with pregnant women, newborn babies, and anyone who is immunocompromised and hasn't had chickenpox. Keep the rash clean, dry, and loosely covered while you recover.

Aciclovir may not be suitable for everyone, and your dose may need to be adjusted if you have reduced kidney function. Let your prescriber know if you're pregnant or breastfeeding, have kidney problems, or take other medicines — they'll only approve treatment if it's safe and appropriate for you.

Contact A&E, call 111, or book an urgent GP appointment if your rash is on or around your eye or eyelid, if you have facial weakness or ear symptoms alongside a facial rash, if you have a widespread rash and are significantly immunocompromised, or if you notice signs of a secondary bacterial infection such as spreading redness, warmth, pus, or fever. These situations need urgent in-person assessment rather than an online prescription.