Both Famvir and Valtrex are used to treat viral infections caused by herpes viruses, including shingles (herpes zoster), genital herpes, and oral herpes (cold sores). Both are antiviral medications, but they contain different active ingredients that are metabolized in the body to form the antiviral active ingredient.
Famvir Tablets Ingredients
Famvir tablets contain the active ingredient famciclovir. Famciclovir is a prodrug that is rapidly converted in the body to penciclovir, the actual antiviral drug that inhibits the replication of herpes viruses by interfering with viral DNA synthesis.
Valtrex Tablets Ingredients
Valtrex tablets contain the active ingredient valacyclovir. Valacyclovir is also a prodrug that is rapidly converted in the body to acyclovir, the actual antiviral drug that inhibits the replication of herpes viruses by a mechanism similar to that of penciclovir.
About Famvir Tablets
Drug Class: Antivirals
Drug Classification: Cyclic guanosine analogue
Pharmaceutical Form: Coated Tablets
Pharmaceutical Family: Drugs for the Treatment of Viral Diseases
Active Ingredient: Famciclovir
About Valtrex Tablets
Drug Class: Antivirals
Drug Classification: Cyclic guanosine analogue (prodrug of acyclovir)
Pharmaceutical Form: Coated Tablets
Pharmaceutical Family: Drugs for the Treatment of Viral Diseases
Active Ingredient: Valacyclovir
Scientific Degree: Pharmacist
Country: Egypt
Dr. Rawan Mosaad El-Saeed is a clinical pharmacist and medical content reviewer holding a Bachelor of Pharmacy degree from Horus University in Egypt. She has hands-on community pharmacy experience in providing medication therapy counseling, monitoring drug-drug interactions, and ensuring patient adherence to safe usage protocols. She specializes in authoring and fact-checking pharmaceutical guides and simplifying clinical pharmacology based on the latest evidence-based guidelines and internationally accredited references, dedicated to delivering accurate, reliable, and safe healthcare information for readers.
Published Date: 23 April 2025
Source 1 :
Drugs Famciclovir
Source 2 :
Drugs Valacyclovir
you should ask your doctor before taking this medicine