Valacyclovir can be taken for years at a time. For short-term treatment of an active outbreak, courses run anywhere from 1 to 10 days depending on the condition. For daily suppressive therapy to prevent recurring outbreaks, many people stay on it continuously for multiple years with a well-documented safety profile. The CDC notes that long-term safety and efficacy have been established for daily use, and that neither treatment discontinuation nor routine lab monitoring is necessary because serious adverse events and antiviral resistance are uncommon.
Short-Term Use for Active Outbreaks
When you’re taking valacyclovir to treat a specific outbreak rather than prevent future ones, the course is brief. For cold sores, treatment can be as short as a single day. For a first genital herpes outbreak, a typical course runs 7 to 10 days. Recurrent genital herpes episodes usually call for 3 to 5 days of treatment. Shingles is treated with a 7-day course, ideally started within 72 hours of the rash appearing.
These short courses are straightforward. You take the medication for the prescribed number of days and stop. There’s no tapering and no need for follow-up bloodwork afterward.
Daily Suppressive Therapy Can Last Years
The question most people are really asking is whether it’s safe to take valacyclovir every day, indefinitely, to keep outbreaks from coming back. The short answer: yes, and many people do exactly that.
The FDA-approved prescribing information notes that formal clinical trial data on suppressive therapy extends to one year in otherwise healthy patients and six months in people with HIV. That doesn’t mean you need to stop at those marks. It simply means the controlled trial data has a defined endpoint. Real-world use, postmarketing surveillance, and the CDC’s treatment guidelines all support longer use. A review published in The Journal of Infectious Diseases analyzed safety monitoring data from clinical trials involving over 3,000 people on long-term suppressive therapy and found that the safety profile of valacyclovir at daily doses was similar to placebo. That analysis drew on more than 20 years of cumulative experience with the drug’s parent compound, acyclovir.
The CDC’s 2021 sexually transmitted infections treatment guidelines are clear: long-term safety and efficacy are documented, and there is no requirement to stop taking the medication or undergo periodic lab monitoring. Antiviral resistance from long-term use is uncommon in people with healthy immune systems.
Annual Check-Ins, Not Mandatory Stopping
The CDC recommends that you and your provider have a conversation once a year about whether to continue suppressive therapy. This isn’t because the drug becomes dangerous over time. It’s because herpes outbreaks tend to become less frequent on their own as years pass, especially with genital HSV-2. Some people who started daily valacyclovir because they were having six outbreaks a year may find, three or four years later, that their body would only produce one or two outbreaks annually without it.
The annual check-in is a chance to weigh whether the medication is still doing meaningful work for you. If outbreaks were your main concern and they’ve naturally tapered, you might try stopping to see what happens. If reducing viral transmission to a partner is the goal, continuing daily therapy may still make sense regardless of outbreak frequency. Stopping valacyclovir doesn’t cause withdrawal or rebound effects. If outbreaks return, you can restart.
Kidney Health Is the Main Safety Consideration
Valacyclovir is processed through the kidneys, and in people with reduced kidney function, the drug and its byproducts can build up to levels that cause neurological side effects like confusion, agitation, or tremors. For people with normal kidney function, this is rarely an issue at standard daily doses.
Before starting valacyclovir, your provider should check your kidney function, particularly if you’re older or have conditions that affect the kidneys. During treatment, staying well hydrated helps your kidneys clear the drug efficiently. If you already have kidney disease, the dose and frequency need to be adjusted downward. For the vast majority of people with healthy kidneys, long-term daily use at suppressive doses doesn’t require ongoing blood tests or special monitoring, per the CDC guidelines.
Drug Resistance Is Rare in Healthy Immune Systems
One concern people have about taking any antiviral for years is whether the virus will stop responding to it. In people with functioning immune systems, herpes developing resistance to valacyclovir is uncommon even after years of continuous use. The CDC specifically addresses this, noting that resistance related to long-term antiviral use is not a significant clinical concern for immunocompetent patients. Resistance is more of a consideration for people with severely weakened immune systems, such as organ transplant recipients or those with advanced HIV, where the virus replicates more aggressively and has more opportunity to mutate.
What Happens When You Stop
Valacyclovir does not cure herpes. It suppresses viral activity while you take it. When you stop, the virus remains in your body and outbreaks can resume. For many people, though, outbreaks after stopping are less frequent than they were before starting suppressive therapy, simply because time has passed and outbreak frequency naturally decreases with age and duration of infection.
There’s no medical danger in stopping abruptly. You don’t need to taper the dose. If you decide to discontinue, the main thing to watch for is whether outbreaks return and how bothersome they are. If they do come back at an unacceptable rate, restarting daily therapy is straightforward. Some people cycle on and off suppressive therapy over the years as their needs change, while others stay on it continuously for a decade or more without issues.