Question: how long does herpes outbreak last on valtrex?
Answer: Valacyclovir (Valtrex) for Cold Sores For cold sores, valacyclovir is usually taken in two large doses of 2,000 mg, split 12 hours apart from each other. Like with other outbreaks of HSV, valacyclovir will speed up the speed at which cold sores heal, but it can still take seven to 10 days for them to fully disappear.