Evidence note 21: Antiviral treatment for shingles and its complications in immunocompetent adults (PDF, 204K, 23secs)
Background
Shingles (herpes zoster) is an acute infection caused by the reactivation of the chicken pox virus (varicella zoster). Following a primary infection with varicella zoster, the virus lies dormant in the dorsal root ganglia until it is reactivated and travels along the sensory nerve fibres to cause a vesicular rash.
Shingles is a self-limiting disease but can be treated with antiviral agents.
Aciclovir, famciclovir and valaciclovir are all licensed for use in the UK for the treatment of shingles. These drugs can be given orally (aciclovir can also be administered intravenously) and treatment should be administered within 72 hours of the onset of the rash. This group of antiviral drugs block virus replication and slow down its spread. Aciclovir (800 mg five times daily for 7–10 days) was the first antiviral developed to treat shingles but has limited oral bioavailability. Famciclovir and valaciclovir were developed to overcome its limitations and have improved pharmacokinetic profiles.3
They have different regimens: 250 mg three times daily or 750 mg daily for 7 days for famciclovir and 1 g three times daily for 7 days for valaciclovir.
Key points
-
Anti-viral drugs – aciclovir, famciclovir and valaciclovir – are all licensed for use in the UK for the treatment of shingles, and should be administered within 72 hours of the onset of the rash.
-
It is clinically proven that antiviral therapy is safe and can accelerate rash healing and reduce the intensity and duration of pain in the acute phase of shingles. There is some evidence that antiviral agents can reduce the duration of PHN, with newer agents being modestly more effective.
-
Antiviral drugs are effective in reducing the frequency and severity of ophthalmic shingles, and can be initiated beyond the recommended 72-hour time frame.
-
Aciclovir is cheaper than famciclovir and valaciclovir as it is available in generic form.
