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Chickenpox - Management
Which antiviral drug should I prescribe for a pregnant woman with chickenpox?

  • Aciclovir is the preferred antiviral drug because of its long-term safety data in pregnant women.
    • A dose of 800 mg five times daily for seven days should be prescribed on the advice of a specialist.
  • Informed consent should be obtained because aciclovir is unlicensed for use in pregnancy.
Basis for recommendation
  • The recommendation to prescribe aciclovir is based on guidance issued by the British Society for the Study of Infection, Public Health Laboratory Services, Royal College of Obstetricians and Gynaecologists, and Health Protection Agency [Ogilvie, 1998; Morgan-Capner et al, 2002; HPA, 2007b; RCOG, 2007].
  • Dose of aciclovir:
  • Aciclovir is preferred over valaciclovir because there are good long-term safety data for aciclovir in pregnant women:
    • Data from the International Aciclovir Pregnancy Registry (1984–1999) found that in the 1234 pregnancies followed, the observed rates and types of birth defects for pregnancies exposed to aciclovir did not differ significantly from those in the general population [Stone et al, 2004].
    • Pregnancy outcomes from 111 prospectively registered pregnancies in the Valaciclovir Pregnancy Registry found no apparent adverse outcomes. However, these data, together with those from other small studies, provide insufficient information for a risk evaluation. Consequently, the use of valaciclovir is not recommended during pregnancy because of insufficient data [Schaefer et al, 2007].
  • Other reasons for preferring aciclovir:
    • Unlike valaciclovir, aciclovir is licensed for the treatment of varicella infections.
    • It is also less expensive than valaciclovir.

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