Highlights
- The generic form — and active ingredient — of Valtrex is valacyclovir.
- Valacyclovir is one of the most commonly prescribed antiviral medications for treatment of herpes simplex (oral or genital herpes) and herpes zoster (chickenpox or shingles) outbreaks in adults.
- Valtrex does not cure herpesviruses, but it does reduce the severity and duration of symptoms.
- On average, expect relief in two to three days.
- Valtrex is generally prescribed for seven to ten days but sometimes longer.
- It’s important to take the entire course, even if you feel immediate relief.
Michael DiLeo, MD, has over 30 years of experience in clinical and academic medicine. Through medical school, residency, and private practice, he has functioned as both a specialist and a primary care practitioner. He has twice served as chief of staff of a large regional hospital. He is a published author on women's health for McGraw-Hill. Learn More
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Valtrex is the brand name for the drug valacyclovir, most commonly used to mitigate infections by the herpesviruses that cause cold sores, genital herpes, and shingles.
Valtrex can also be prescribed to shorten the duration and severity of chickenpox outbreaks in adults. While Valtrex does not cure the herpes infection, it usually makes the outbreaks shorter and less severe. People who get frequent outbreaks of cold sores or genital herpes can take the drug as soon as the warning symptoms appear to help make the outbreak as mild as possible.
In addition to these common uses for Valtrex, the drug is also used in other, less common situations. For example, it can be used to treat herpes infections of the eye and can help prevent certain viral infections in people who have had organ transplants. The FDA approved Valtrex in 1995, and the drug has a long and proven history of helping people cope with herpes outbreaks.
How Long Does Valtrex Take to Work?
How long it takes Valtrex to work depends on several factors, including the severity of the outbreak and how quickly you take it after an outbreak starts. Valtrex is usually prescribed for a 7- to 10-day course of treatment, which is close to the time it takes for the herpes blisters to heal. But if your doctor prescribes the drug for a longer period, you should take it for the entire period, even if you feel relief quickly. Valtrex has a half-life of approximately 2.5 to 3.3 hours in the body, depending on the person and the dosage.
For people who have repeated herpes outbreaks and are familiar with the signs that precede an outbreak, the drug may be prescribed for a shorter duration of around five days. Many people who take Valtrex notice some relief from symptoms, also called onset of action, within two or three days with the healing of the blisters after about a week. Again, the sooner during an outbreak a person starts taking Valtrex, the shorter and less severe the outbreak generally is.
Some report lessening of pain within hours, but it is unknown whether it is actually impacting the virus that fast or is just a placebo result. The placebo result is not far-fetched, however, since stress has been known to provoke an outbreak. Psychological states often impact the body’s immune system.
How Valtrex Works
Valtrex is what’s known as a prodrug of acyclovir. This means the body converts Valtrex to acyclovir after absorption. The result is that Valtrex has a higher efficacy than standard acyclovir, so that it has to be taken fewer times per day. Valtrex works by preventing the virus from replicating so herpes infects fewer cells within the body.
Once inside infected cells, the drug blocks the action of an enzyme called DNA polymerase. Herpesviruses need this enzyme to make copies of themselves — Valtrex blocks DNA polymerase, so the virus isn’t able to multiply. The result is an infection that’s less severe and that the immune system has an easier time coping with. Valtrex may have more side effects than acyclovir, but they tend to have similar drug interactions.
Valtrex for Genital Herpes – Short-term Use
The herpes simplex viruses (HSV-1 and HSV-2) cause cold sores and genital herpes. However, although the majority of cold sores are a result of HSV-1 and genital lesions are a result of HSV-2, either virus can cause either type of outbreak. The viruses don’t leave the body after an outbreak. Instead, they go dormant until they’re triggered by factors like stress, diet, alcohol, or respiratory infections. A majority of Americans are infected with herpesviruses, but only around one-third ever have an outbreak. Some people have an initial outbreak and then never have another one.
After infection, people with HSV-1 tend to have fewer and less severe outbreaks than those with HSV-2, but this isn’t always the case. A minority of people infected with either type of herpes, however, have repeated outbreaks. For these people, Valtrex can make a big difference in quality of life.
Long-term Valtrex Use for Those with Frequent Flare-ups
People who have frequent outbreaks of herpes, whether in the form of cold sores or genital herpes, may be prescribed long-term treatment with Valtrex to minimize these outbreaks. Taking the drug regularly can help those who get frequent outbreaks suppress the virus and keep recurrences to a minimum. This therapy can also help reduce the risk of passing genital herpes to a sex partner, as long as safe sex practices (condoms) are used as well. While people with herpes should avoid sexual contact whenever sores are present, it is also possible to spread it without overt lesions, called “silent shedding.”
Valtrex Use in Organ Transplant Patients
In addition to its use for herpesviruses, Valtrex has another long-term use — doctors also prescribe it for cytomegalovirus (CMV). CMV is a related virus that can also lie dormant in the body for long periods of time. Like the herpesviruses, CMV is present in a large proportion of the population.
In healthy individuals, a CMV outbreak may go entirely unnoticed or produce mild, cold-like symptoms, but for some people, CMV can be life-threatening. People with HIV, newborns, other immunocompromised people, and those who have received transplanted organs are in danger of life-threatening CMV outbreaks. In these people, who have compromised immune systems, Valtrex may be prescribed long term to prevent CMV outbreaks.
Living with Herpes Outbreaks
For most people, cold sores and genital herpes may be painful and inconvenient, but they are not life-threatening. However, genital herpes may increase your risk of contracting HIV because the blisters offer the virus easier entry into the body. That’s why it’s critical to use safe sex practices and inform partners if you have genital herpes.
To manage an outbreak of cold sores or genital herpes, take prescription antiviral medication like Valtrex as directed, keep the affected areas clean and dry, and avoid direct contact with others. Don’t share towels, clothing, or eating utensils, and manage pain with over-the-counter medications like Advil or Tylenol if your doctor approves it.
If you get repeated outbreaks, speak with your doctor about how to recognize symptoms of an oncoming outbreak so you can treat it as promptly as possible.
eDrugstore Can Help You Manage Herpes
Getting Valtrex doesn’t have to be a hassle when you work with online facilitators like eDrugstore. We are committed to the health and well-being of all our customers, and we dispense Valtrex using U.S.-licensed pharmacists as prescribed by U.S.-licensed physicians, with free telehealth consultation.
We also ship promptly — often on the same day an order is placed. We’re dedicated to exceptional customer service, privacy, and the highest standards for secure online ordering. With eDrugstore, you can order Valtrex or valacyclovir with confidence.
Dan is a long-time freelance writer focusing on technology, science, health, and medicine, with a lifelong interest in physics, biology, and medicine. His work has taken a particular focus on scientific studies “beyond the headlines,” reading the study to more closely examine the results.