Based on the information available, there is no direct replacement for Famciclovir specifically during pregnancy. Famciclovir is a medication used to treat various viral infections, including herpes simplex and varicella-zoster (shingles) [1].

However, in pregnancy, the use of medications should be carefully considered, weighing the potential risks and benefits. The U.S. Food and Drug Administration (FDA) categorizes medications based on their risk during pregnancy [2]. Famciclovir is classified as a Category B drug, which means it's believed to be safe, but more research is needed [1].

In pregnancy, when a drug like Famciclovir is not recommended, the treatment approach often involves careful monitoring and, if necessary, the use of antiviral medications that have a longer history of use in pregnancy or are considered safer [3]. For instance, Aciclovir, another antiviral drug, is often used and is categorized as a Category B drug by the FDA [2][4].

Please consult with a healthcare provider for personalized medical advice, as each case is unique and should be treated accordingly.

Sources:
[1] "Famciclovir" (Famvir) [Drugs.com]
<https://www.drugs.com/famciclovir.html>
[2] "Pregnancy Categories (A, B, C, D, X)" [FDA]
<https://www.fda.gov/media/76942/download>
[3] "Antiviral Therapy and Counseling for Patients with Genital Herpes" [CDC]
<https://www.cdc.gov/std/hiv/antiretroviral/genital-herpes.html>
[4] "Aciclovir" (Zovirax) [Drugs.com]
<https://www.drugs.com/aciclovir.html>

Additional source for DrugPatentWatch.com:
[5] "Famciclovir" [DrugPatentWatch.com]
<https://www.drugpatentwatch.com/drugs/famciclovir>