Valtrex and Genital Herpes

Episodic treatment

Valacyclovir is used to treat first episode and recurrent outbreaks of genital herpes. It slows down the spread of the herpes virus, reduces the duration and severity of outbreak, and viral shedding.

A burst of virus replication occures in the first 24 hours of a herpes outbreak. So the reatment of recurrent episode is most effective if started within one day of the appearance of symptoms. Valacyclovir may prevent the development of painful vesicular genital lesions when used promptly within 6 hours of the first sign of the attack4.

Dosage for genital herpes:

  • Initial episode: 1 g twice daily for 10 days.
  • Recurrent episode: 500 mg twice daily for 3 days.

When is the best time to take Valtrex?
Valacyclovir works by stopping viral replication. The period of herpes virus replication is early and brief. So, valacyclovir works best if started at the first signs of an outbreak within 48 hours.


Valacyclovir is used to prevent recurrent outbreaks of genital herpes. Valacyclovir suppressive therapy is very effective: it reduces the frequency of recurrence by up to 75% and also reduces asymptomatic viral shedding between outbreaks2.

Dosage for suppressive therapy:

  • In persons with 10 or more recurrences per year the most effective dosing regimens are 1 g daily or 250 mg twice daily3.
  • In persons with <9 recurrences per year: 500 mg once daily.

Reduction of transmission

In 2003 the U.S. FDA approved Valtrex for reduction of transmission of genital herpes to an uninfected sexual partner. In fact, transmission frequently occurs during periods of asymptomatic viral shedding.

Can you spread herpes (HSV) while taking Valtrex? Valacyclovir significantly reduces the chances of spreading herpes, but does not eliminate the risk completely.

Effectiveness in preventing HSV transmission: Valacyclovir reduces the overall risk of transmission of genital infection (HSV-2 seroconversion) by 48% and the risk of transmission of symptomatic genital herpes by 75%1, when used in combination with safer sex practices.

Dosage for reduction of transmission: 500 mg once daily in source partner.

See also


  • 1. Leone P. Reducing the risk of transmitting genital herpes: advances in understanding and therapy. Curr Med Res Opin. 2005 Oct;21(10):1577-82. PubMed
  • 2. Patel R, Bodsworth NJ, Woolley P, Peters B, Vejlsgaard G, Saari S, et al. Valaciclovir for the suppression of recurrent genital HSV infection: a placebo controlled study of once daily therapy. Genitourin Med. 1997;73:105–9.
  • 3. Reitano M, Tyring S, Lang W, et al. Valaciclovir for the suppression of recurrent genital herpes simplex virus infection: a large-scale dose range-finding study. J Infect Dis. 1998 Sep;178(3):603-10.
  • 4. Strand A, Patel R, Wulf HC, Coates KM; International Valaciclovir HSV Study Group. Aborted genital herpes simplex virus lesions. Sex Transm Infect. 2002 Dec;78(6):435-9.
  • 5. Wald A, Selke S, Warren T, Aoki FY, Sacks S, Diaz-Mitoma F, Corey L. Comparative efficacy of famciclovir and valacyclovir for suppression of recurrent genital herpes and viral shedding. Sex Transm Dis. 2006 Sep;33(9):529-33.

Author: OriginalDrugs Team
Last reviewed: February, 2015

Quick facts

  • Valacyclovir may work somewhat better than famciclovir (Famvir) for suppression of genital herpes and viral shedding5.