Antivirals for shingles


Generic Name Brand Name
acyclovir Zovirax
famciclovir Famvir
valacyclovir Valtrex

How It Works

Antiviral medicines prevent the virus that causes shingles from multiplying. These medicines shorten the period of rash, decrease pain during the active stage of the illness, and reduce the possibility of getting complications of shingles, such as postherpetic neuralgia. Antivirals may be taken orally (by mouth) or injected intravenously (in a vein).

Why It Is Used

Anyone who has shingles can use antivirals, but antivirals are particularly beneficial for adults older than 50 and people with weak immune systems. They are also used for people with severe rash and those who have rash near an eye and/or on the forehead.

How Well It Works

Antivirals may reduce the severity of shingles and speed healing. When acyclovir, famciclovir, or valacyclovir are taken within 72 hours of getting shingles, these medicines can significantly reduce the duration of pain associated with shingles. These medicines also reduce the pain caused by postherpetic neuralgia.1, 2

Side Effects

Antivirals have few side effects but may cause headache, nausea, and loss of appetite.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

If you have kidney problems, you may need to take less than the typical dosage of antiviral medicine. Before you start antiviral treatment, be sure your doctor is aware of your other medical conditions.

If you have a weakened immune system, as may happen to people with diseases such as HIV or diabetes, your doctor may inject antiviral medicines into your vein (intravenously).

Topical antivirals (put on the skin) do not help treat shingles.

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  1. Habif TP, et al. (2005). Herpes zoster (shingles). In Skin Disease: Diagnosis and Treatment. 2nd ed., pp. 210–215. Philadelphia: Elsevier Mosby.
  2. Wareham D (2007). Postherpetic neuralgia, search date December 2006. Online version of Clinical Evidence:

Last Updated: March 9, 2009

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