Dosing: Oral. 2 gram pill twice (every once every 12 hours) for one day. Must be taken at the first sign
or symptom of a cold sore before visible symptoms, for the drug to work. Preferably should be taken in
the first hours after a tingle.

Efficacy:
       Duration: Reduces duration of outbreaks by 1 day, from about 6 days to about 5 days.

 

       Severity of outbreaks: Does not reduce severity of an outbreak. “No significant difference was
observed between subjects receiving VALTREX or placebo in the prevention of progression of cold
sore lesions beyond the papular stage.”
 

       Prevention: VALTREX is not approved for prevention of outbreaks.
 

      

Mechanism of Action: Inhibits DNA replication of herpes viruses. Valacylovir is broken down in the body to acyclovir. Acyclovir is phoshporaylated by the herpes virus thymidine kinase (TK). The
phosphorylated acyclovir then inhibits the herpes virus DNA polymerase.

​

Side Effects: Headache and dizziness and abnormal liver test marker (ALT) were more common in
patients receiving VALTREX than placebo.

 

References:

VALTREX prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/2008/020487s014lbl.pdf

 

Spruance SL, Jones TM, Blatter MM, Vargas-Cortes M, Barber J, Hill J, Goldstein D, Schultz M. High-dose, short-duration, early valacyclovir therapy for episodic treatment of cold sores: results of two randomized, placebo-controlled, multicenter studies. Antimicrob Agents Chemother. 2003 Mar;47(3):1072-80. doi: 10.1128/AAC.47.3.1072-1080.2003. PMID: 12604544; PMCID: PMC149313.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC149313/

 

More information:  https://www.drugs.com/valtrex.htlm