Valtrex before and after


Valacyclovir 101: How it Works, Side Effects & More

Valacyclovir is an antiviral medication that’s used to treat herpes and cold sores. It’s sold under several brand names, the most common of which are “Valtrex” and “Zelitrex.”

Valacyclovir is one of the most commonly used herpes treatments. It’s used to manage both of the herpes simplex viruses, HSV-1 (cold sores) and HSV-2 (genital herpes). It’s also used in the management of singles, or herpes zoster.

If you have herpes, it’s extremely likely that you’ll be prescribed either valacyclovir or a similar drug in order to manage the virus. Valacyclovir is highly effective in managing herpes. It’s also an extremely safe, well studied medication.

In this guide, we’ll go over what valacyclovir is, how it works and the potential side effects you can expect from using it as part of herpes management. We’ll also look at how long it can take for valacyclovir to become effective, as well as changes you may need to make to your habits.

What is Valacyclovir?

Valacyclovir is an antiviral medication that’s designed to treat HSV (herpes simplex virus) and VZV (varicella-zoster virus, more commonly known as chickenpox) infections.

The drug works by slowing down the growth of herpes, making it easier for the body to control the infection. Valacyclovir itself is a prodrug (meaning it converts into another substance in the body), that converts into acyclovir after it passes through the liver.

Compared to acyclovir, which is also used as an antiviral herpes medication, valacyclovir has a far higher level of bioavailability, meaning more of the drug will make it into your body than other herpes drugs that are broken down by the liver.

Valacyclovir treats several species of the herpes virus, ranging from HSV-1 and HSV-2 to VZV (chickenpox), the Epstein–Barr virus (known as HHV-4, which is associated with some forms of cancer) and cytomegalovirus (CMV).

Of these viruses, valacyclovir is most effective against HSV, making it one of the most widely prescribed drugs for people with herpes.

Valacyclovir is an extremely well studied medication, with a huge amount of scientific evidence to back up its efficacy and safety record. It’s used to treat people of all ages, from children that suffer from chickenpox to adults with cold sores and recurrent genital herpes.

Since it was introduced in the 1980s, valacyclovir has been widely used to successfully control and treat herpes, so much so that it and similar drugs are listed as the “gold standard” in herpes treatment in studies.

How Valacyclovir (Valtrex) Works

Valacyclovir works through a complex chemical process that interferes with the mechanism the herpes virus uses to reproduce, preventing it from multiplying and reducing the rate at which the infection spreads.

In short, valacyclovir stops the herpes virus from spreading to healthy cells, reducing the effects of the virus.

It’s important to know that valacyclovir doesn’t cure herpes. However, it does make the effects of herpes less severe, meaning the sores developed from the virus heal faster and the aches, cold symptoms and other signs of herpes can become less severe.

If you have herpes, valacyclovir reduces the risk of you transmitting the virus to other people. In one study, researchers found that people with HSV-2 were almost 50% less likely to transfer the virus to their sexual partners than people with HSV-2 that didn’t use medication.

How Long Does Valacyclovir Take to Work?

The amount of time required for valacyclovir to control a herpes or chickenpox outbreak varies based on the severity of the outbreak and how soon you take valacyclovir after noticing herpes symptoms.

For most initial herpes outbreaks and cases of recurring herpes, valacyclovir takes effect very quickly and provides some level of relief in as little as two to three days. Generally, the sooner you take valacyclovir after noticing symptoms, the faster it will be to provide relief.

It’s important to remember that every outbreak is different, meaning valacyclovir can potentially take less or more time than the figures listed above to provide relief and control over a shingles infection or herpes outbreak.

Our guide to how long valacyclovir (Valtrex) takes to become effective covers more about valacyclovir’s onset of action and average time to start working for different viral injections.

Valacyclovir Brand Names, Dosages and Interactions

Valacyclovir is available as a generic medication or under several brand names. In the United States, valacyclovir is most commonly sold as Valtrex and Zelitrex, which are the original trade names for the drug marketed by GlaxoSmithKline.

Today, valacyclovir is available as a generic medication, meaning there are numerous different trade names in use. Most of the companies manufacturing valacyclovir offer it in several doses, including 500 mg and 1,000 mg tablets.

The recommended dosage of valacyclovir varies based on the type of HSV or VZV virus that’s being treated, as well your age. Generally, the most common dosages are as follows:

  • For adults with shingles, 1,000 mg of valacyclovir three times daily, for a total of seven days. It’s recommended to begin treatment within 72 hours of noticing shingles.
  • For adults with cold sores, a dose of 2,000 mg of valacyclovir is typically used, with a secondary dose of 2,000 mg within 12 hours.
  • For adults treating a first outbreak of genital herpes, 1,000 mg of valacyclovir two times daily for a total of 10 days. It’s recommended to begin treatment within 48 hours of the herpes symptoms becoming noticeable.
  • For adults with recurring genital herpes, 500 mg of valacyclovir two times daily for a total of three days. It’s recommended to begin valacyclovir treatment as soon as a recurrent herpes symptom becomes visible.

It’s important to note that these are typical dosages and may not be appropriate for you based on your symptoms, age, body weight and general health. The best approach for treating any virus, including HSV or VZV, is talk to your doctor and follow their treatment advice.

It’s especially important to talk to your doctor if you have a weakened immune system or kidney disease, as these health conditions can affect the safety of valacyclovir treatment. Breastfeeding or pregnant women should also discuss the risks of valacyclovir treatment with their doctor.

Valacyclovir is known to potentially interact with other antiviral and immunosuppressant drugs, particularly those used in HIV/AIDS management. Medications that can potentially interact with valacyclovir include foscarnet, tenofovir, mycophenolate, zidovudine and the varicella virus and zoster virus vaccines.

If you use any of these medications, you should discuss potential interactions with your doctor before considering valacyclovir or any other herpes treatment.

Valacyclovir Side Effects

Valacyclovir has several potential side effects, the most common of which (affecting more than one percent of users) are vomiting, diarrhea, headache and nausea.

Less common side effects (affecting less than one percent of users) include the following:

  • Vertigo
  • Dizziness
  • Confusion
  • Sore throat
  • Rash
  • Renal impairment
  • Constipation
  • Abdominal pain
  • Agitation
  • Edema
  • Weakness

Very uncommon side effects (affecting less than 0.1% of users) include the following:

  • Seizures
  • Neutropenia
  • Leukopenia
  • Fatigue
  • Anorexia
  • Anaphylaxis
  • Stevens-Johnson syndrome
  • Hepatitis
  • Toxic epidermal necrolysis
  • Psychotic symptoms

Learn More About Valacyclovir (Valtrex)

Valacyclovir is one of the most common herpes medications, meaning it’s very likely to be your first choice if you’re dealing with an HSV-1 (cold sores) or HSV-2 infection (genital herpes). Our guides to valacyclovir cover every aspect of the medication, including:

  • How Long Does Valacyclovir (Valtrex) Take to Work?
  • Valacyclovir Dosage Guide: Cold Sores, Genital Herpes & More
  • Valacyclovir vs. Alternative Herpes Treatments: Which is Best?
  • A Complete Guide to Valacyclovir (Valtrex) Side Effects
  • Valacyclovir (Valtrex) Oral Medication vs. Cream: Which is Best?
  • Can You Drink Alcohol While Taking Valacyclovir (Valtrex)?
  • Does Valtrex Prevent HPV Transmission?

How Long Does Valacyclovir (Valtrex) Take to Work?

Valacyclovir (commonly sold as Valtrex) is one of the most widely used and effective drugs on the market for treating and controlling cold sores, shingles and genital herpes.

While valacyclovir isn’t a cure for herpes, it can help to treat the physical symptoms of HSV-1 and HSV-2. Valacyclovir is also commonly prescribed for chickenpox, which is caused by the varicella zoster virus (VZV).

The amount of time required for valacyclovir to start working can vary based on a number of factors, ranging from the type of infection you have to your valacyclovir dosage and the total amount of time that passes after you notice symptoms but before you start treatment.

In this guide, we’ll look at some of the most common situations in which you’d use valacyclovir for treatment, as well as the approximate amount of time it should take for valacyclovir to offer relief.

>>MORE: How to get rid of a cold sore quickly.

Valacyclovir for First Herpes Outbreaks

For first-time herpes outbreaks, valacyclovir is most effective when it’s used within 48 hours of symptoms appearing.

The standard dosage of valacyclovir for first-time herpes outbreaks is 1,000 mg two times per day over a period of 10 days. Valacyclovir usually starts treating herpes symptoms as soon as it’s in your system, but can take several days to produce a noticeable improvement.

It can take up to 10 days (or, in some cases, even longer) for herpes blisters to heal even with valacyclovir treatment. This makes it important to start treatment as soon as you notice herpes symptoms.

In some cases, your doctor might prescribe valacyclovir for a longer period than 10 days or at a different dosage. In this case, follow your doctor’s instructions and make sure you complete the full course of the medication, even if the herpes blisters heal before the end of the period.

Valacyclovir for Recurrent Herpes Outbreaks

Herpes can remain dormant in the body for weeks, months or years in between outbreaks. On average, people with HSV-1 experience about one outbreak per year, while people with HSV-2 will usually experience four to five outbreaks per year.

When these outbreaks occur, valacyclovir can provide fast and effective relief, helping to control herpes outbreak symptoms.

The typical valacyclovir dosage for recurrent herpes outbreaks is 500 mg two times per day over a period of three days. Like with first-time herpes outbreaks, valacyclovir is most effective when it’s taken as soon as you notice a herpes outbreak developing.

When taken as soon as you notice a herpes outbreak, valacyclovir can provide relief in as little as two to three days, minimizing symptoms and reducing the risk of you passing genital herpes to sexual partners.

>>MORE: HSV 1 vs. HSV 2 – What’s the difference?

Valacyclovir for Shingles

Valacyclovir is usually prescribed for seven days for shingles, with a typical dosage of 1,000 mg three times per day.

Just like with HSV-1 and HSV-2, it’s important to start treatment as soon as you notice shingles symptoms. Most experts recommend starting valacyclovir within 72 hours of noticing symptoms for the best results.

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.

Worried About Herpes? Act Quickly for Faster Relief

From cold sores to genital herpes, acting quickly helps you treat and control a herpes outbreak in the shortest amount of time. For this reason, most doctors recommend using valacyclovir in the first 24-72 hours after noticing a cold sore or other herpes blister developing.

If you’ve noticed a cold sore or any of the other symptoms of a herpes outbreak, it’s best to talk to your doctor about treatment and relief options as soon as possible.

>>MORE: Is valacyclovir your best option? Read about others here.

In This Section

  • Oral & Genital Herpes
  • What are the symptoms of herpes?
  • Should I get tested for herpes?
  • How do I get treatment for herpes?
  • How is herpes prevented?
  • Living with herpes

There’s no cure for herpes. But you can take medicine that makes outbreaks shorter and less painful, and can help prevent outbreaks in the future.

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Want to get tested for herpes?

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What’s the treatment for herpes?

Even though there’s no cure for herpes, there are plenty of ways to treat the symptoms and manage the infection. Herpes medicine makes outbreaks go away sooner and/or prevents them from coming back as often. Your doctor will tell you about the best treatment options for your situation.

If you’re having an outbreak, your doctor can give you medicine to help heal your sores faster. You can also help ease the pain by:

  • taking a warm bath

  • keeping your genital area dry (moisture makes the sores last longer)

  • wearing soft, loose clothes

  • putting an ice pack on the sores

  • taking a pain reliever like aspirin, ibuprofen (Advil, Motrin), or acetaminophen (Tylenol).

How can I prevent herpes outbreaks?

If you have lots of herpes outbreaks, your doctor may tell you to take medicine every day — this is called suppressive therapy. It can help prevent future herpes outbreaks, and lower your chances of giving herpes to your partners.

Whether or not you take medicine to treat herpes, taking care of yourself by eating healthy foods, getting enough sleep, and avoiding stress might help keep future outbreaks from popping up.

No one knows for sure what triggers genital herpes outbreaks. Other infections, surgery, sex, your period, skin irritations, and stress may cause outbreaks. Sunburns, injuries to your lips, or other infections can cause oral herpes flare-ups. Try to avoid getting sunburned if you have oral herpes.

Genital herpes outbreaks usually happen less often and become shorter and weaker after a few years — whether or not you get treated.

What happens if you don’t get herpes treatment?

The good news about herpes is that it’s not deadly or even very dangerous. It might be annoying, but herpes doesn’t get worse over time or cause serious health problems like other STDs can.

If you don’t get treated for herpes, you might keep having regular outbreaks, or they could only happen rarely. Some people naturally stop getting outbreaks after a while.

There are a few reasons people may decide not to get treatment. They might not have that many outbreaks, or their outbreaks don’t really bother them. Or maybe they’re not having sex, so they’re not that worried about having herpes right now. Whatever your situation is, getting treatment for herpes is your choice.

Having herpes can make it easier to get HIV, because the sores give HIV an open pathway into your body. So always use condoms to help prevent the spread of both herpes and HIV.

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Valacyclovir for Episodic Treatment of Genital Herpes: A Shorter 3-Day Treatment Course Compared with 5-Day Treatment


Valacyclovir given in a 5-day regimen of 500 mg twice per day is effective as short-term treatment of episodes of recurrent genital herpes. This study compared the efficacy of a shorter, 3-day course (for 402 patients) with that of a 5-day course (for 398 patients) of valacyclovir for persons with frequent recurrence of symptoms. No significant differences were detected between the 2 dosing schedules for any of the end points measured. Median times to lesion healing, of pain duration, and of episode length for the 5-day versus 3-day treatment were 4.7 versus 4.4 days, 2.5 days versus 2.9 days, and 4.4 days versus 4.3 days, respectively. The proportions of patients with aborted lesions were 26.6% and 25.4% in the 5-day and 3-day groups, respectively. A 3-day course of 500 mg of valacyclovir administered twice daily as episodic treatment of recurrent genital herpes is equivalent to a 5-day course with regard to key markers of efficacy.

Genital herpes is one of the most prevalent sexually transmitted diseases in the world today: ∼1 in 5 adults in the United States is seropositive for herpesvirus type 2 (HSV-2) . Although the disease itself is generally not life-threatening, it has significant morbidity and impact on patients’ lives . Presently, no cure is available for the condition, but treatment strategies are available to alleviate the acute symptoms of a herpes outbreak or to suppress recurrences.

Orally administered antiviral therapy for genital herpes is prescribed either to alleviate the acute symptoms and signs of an outbreak (i.e., episodic treatment) or to prevent the herpesvirus (HSV) reactivation and recurrent outbreaks (i.e., suppressive therapy). The specific aims of episodic treatment are to shorten the duration of the outbreak, reduce the severity of pain, and hasten lesion healing. Prompt treatment, starting within a few hours after the patient first detects symptoms of an outbreak, can halt the process of vesicular lesion development (i.e, aborted lesions) .

Valacyclovir, the l-valine ester of acyclovir, is widely used to treat genital herpes, both as episodic therapy administered twice daily and as suppressive therapy administered once daily. In controlled, randomized trials using lesion healing, pain, and HSV shedding as measures of clinical efficacy for 5 days, valacyclovir has been shown to be as effective as orally administered acyclovir (200 mg 5 times daily) as episodic treatment for genital herpes recurrences .

This double-blind, controlled study compared the efficacy and safety of a 5-day regimen of valacyclovir (500 mg b.i.d.) with a 3-day regimen of valacyclovir (500 mg b.i.d.) for the treatment of a single recurrent genital herpes episode. If a 3-day course of treatment is equivalent in efficacy to the 5-day course, then the reduced therapy duration could increase convenience to patients who prefer discreet, episodic medication regimens and could reduce the cost of treatment.

Patients and Methods

Study design. This study was a randomized, double-blind comparison of the efficacy of valacyclovir administered orally for 5 days versus 3 days in the treatment of a single recurrent genital herpes episode in otherwise healthy adults. It was conducted at 48 medical centers, including 34 medical centers in the United States and 14 in Canada. The study protocol was approved by the institutional review board at each study site. A flow chart of the study is shown in figure 1.

Figure 1

Flow chart of participants and treatment completed in a comparative study of 3- and 5-day regimens of valacyclovir for the episodic treatment of genital herpes.

Figure 1

Flow chart of participants and treatment completed in a comparative study of 3- and 5-day regimens of valacyclovir for the episodic treatment of genital herpes.

Written informed consent was obtained from patients, who were then screened for eligibility on the basis of the findings of a medical history, physical examination, and blood testing. Patients enrolled in the study were given a 3-day supply of open-label valacyclovir (500 mg b.i.d.) and instructed to self-initiate treatment no later than 24 h after the first sign or symptom of a recurrence of their genital herpes. They were asked to return to the clinic within 24 h of initiating treatment. At this initial visit to the clinic for a treated recurrence, patients were stratified by sex and randomized into the 2 blinded treatment groups and provided with 2 additional days’ worth of either valacyclovir (500 mg) or placebo.

Patients were asked to maintain a daily diary to record data regarding lesion stages (prodromal, macule/papule, vesicle/pustule/ulcer, crust, or healed), pain severity (none, mild, moderate, or severe), adverse events, concomitant medications, and compliance with the study drug regimen. Patients were evaluated in the clinic daily for 6 consecutive days and, if necessary, twice per week thereafter, until all lesions were healed and clinical symptoms were absent. Clinical assessments included review of the diary information and an assessment of lesion stages by the investigator. The investigator was permitted to override patient diary data that were inconsistent with clinical findings.

Patients. Participants in this study were patients aged ⩾18 years who were otherwise healthy and who had a history of ⩾4 episodes of genital or perianal HSV outbreaks in the previous year or 2 episodes in the previous 6 months. Confirmation of genital HSV infection was required for study entry. Confirmation could be done by means of culture, direct antigen detection tests, Tzanck smears, immunofluorescence assays, or be means of a written confirmation by a primary-care doctor. Patients who received suppressive therapy with acyclovir during the 12 months before the study were eligible if they had experienced ⩾1 recurrence within 3 months after discontinuation of therapy and within 3 months before study entry.

Patients were excluded if they were currently receiving probenecid, had received systemic antiviral treatment in the 7 days before the first dose of the study drug, or had received an investigational drug or immunomodulatory treatment in the 30 days before receiving the study drug. Immunocompromised patients, those with known HIV infection, and those with renal impairment (creatinine clearance, ⩽30 mL/min) or hepatic impairment (⩾5-fold increase in alanine transaminase level above the normal upper limit) were also excluded from the study, as were persons with a history of hypersensitivity to acyclovir. Other patients excluded from the study were pregnant women, nursing mothers, and sexually active women of childbearing age who were not using an effective and acceptable method of contraception (i.e., oral contraceptives, diaphragm, condoms, or an intrauterine device).

Efficacy end points. The primary end point of the study was the time to lesion healing, which was measured as the number of days from initiation of therapy to reepithelialization of all lesions. Patients whose lesions aborted or who had clinical symptoms but who did not develop lesions were excluded from the analysis of the primary end point.

The secondary end point of this study was duration of pain, measured as the number of days from initiation of treatment or start of pain or discomfort (whichever was later) to the complete cessation of pain. Other secondary end points included length of the episode and the occurrence of aborted lesions. The length of episode was measured as the number of days from initiation of treatment to complete resolution of all signs and symptoms. All patients, including those with aborted lesions, were included in this analysis. Patients whose lesions aborted were defined as those whose lesions did not progress beyond the macule/papule stag, or as those who had clinical symptoms, such as pain, but who did not develop lesions.

Statistical analysis. The intent-to-treat population was defined as all randomized patients. It was presumed that ∼30% of treated patients would not develop lesions and, thus, would not be included in the analysis of the primary end point (i.e., time to lesion healing).

The distributions of times to lesion healing, cessation of pain, and cessation of all symptoms and signs were estimated by the Kaplan-Meier product-limit method. Equivalence in time to lesion healing, duration of pain, and length of episode was assessed by a 95% CI for the Hodges-Lehman estimate of the treatment difference. A difference of <20% from the median time to event for the 5-day regimen was not considered clinically significant. The 400 treated patients per study group provided µ80% power to establish equivalence.

Hazard ratios and 95% CIs were calculated for each time-to-event end point by use of Cox’s proportional hazard models, controlling for the patients’ sex and the analysis center. The validity of the proportional hazard model (the hazard ratio did not change with time) was checked by plotting the log of the negative log of the survival distributions against time. The Cochran-Mantel-Haenszel test was used to test for treatment differences in proportions of patients with aborted lesions, adjusting for the patients’ sex and analysis center.


A total of 1170 patients were enrolled in the study, of whom 800 were randomized to receive the 5-day regimen of valacyclovir (398 patients) or the 3-day regimen of valacyclovir followed by placebo on days 4 and 5 of treatment (402 patients). The majority of the 370 patients enrolled but not randomized did not experience a genital herpes recurrence during the study period. Of those randomized, 362 (91%) of 398 patients in the 5-day group and 359 (89%) of 402 patients in the 3-day group completed the study (figure 1). In each treatment group, the majority of patients who did not complete the study (31 patients in the 5-day group and 35 patients in the 3-day group) discontinued the study as a result of a protocol violation. The other persons who did not complete the study did not return for follow-up visits or voluntarily withdrew from participation.

Demographic and disease characteristics of randomized patients are presented in table 1. Compliance with dosing was high: 99% of patients were reported to have continued use of the study medication until the end of the dosing period.

Table 1

Demographics and disease characteristics of randomized patients in a comparative study of 3- and 5-day regimens of valacyclovir for the episodic treatment of genital herpes.

Table 1

Demographics and disease characteristics of randomized patients in a comparative study of 3- and 5-day regimens of valacyclovir for the episodic treatment of genital herpes.

Efficacy. In the intent-to-treat analysis, the median time to lesion healing (table 2) was 4.7 days in the valacyclovir 5-day group (292 developed lesions) and 4.4 days in the 3-day group (299 developed lesions). The Kaplan-Meier plot for lesion healing is illustrated in figure 2. No significant differences in time to lesion healing were noted between treatment groups by either method of analysis.

Table 2

Median time to event efficacy end points, with Hodges-Lehman estimates of treatment differences and 95% CIs for differences, in a comparative study of 3- and 5-day regimens of valacyclovir for the episodic treatment of genital herpes.

Table 2

Median time to event efficacy end points, with Hodges-Lehman estimates of treatment differences and 95% CIs for differences, in a comparative study of 3- and 5-day regimens of valacyclovir for the episodic treatment of genital herpes.

Figure 2 Figure 2

The duration of pain and length of episodes were similar in both treatment groups, with no significant differences between persons who received the 5-day and 3-day dosing regimens for either end point (table 2). To satisfy the proportional hazard assumption, the patients’ sex was included in the Cox model as a stratification variable for duration of pain and as a covariate for length of episode. In men, the median duration of pain was 2.0 days for the valacyclovir 5-day group and 2.4 days for the valacyclovir 3-day group. The difference in duration of pain was not statistically significant (P = .2563). Because the 95% CI is 20% of the 5-day group’s median duration of pain, the 2 regimens are considered to be equivalent. Women experienced a longer duration of pain, with a median duration of 2.9 days for the valacyclovir 5-day group and 3.0 days for the valacyclovir 3-day group. (P = .0773; table 3). For length of episode, the effect of the patients’ sex in the Cox proportional hazard model was statistically significant (hazard ratio, 0.81; 95% confidence limits, 0.70, 0.95).

Table 3

Median duration of pain for persons enrolled in a comparative study of 3- and 5-day regimens of valacyclovir for the episodic treatment of genital herpes.

Table 3

Median duration of pain for persons enrolled in a comparative study of 3- and 5-day regimens of valacyclovir for the episodic treatment of genital herpes.

Prevention of lesion progression beyond the macule/papule stage (i.e., progression to aborted lesions) was reported by ∼26% of patients. No differences were detected between the valacyclovir 5-day and valacyclovir 3-day treatment groups (26.6% vs. 25.4%, respectively), as shown by an RR of 1.04 and 95% confidence limits of 0.83 and 1.32.


The results of this study indicate that a shorter 3-day course of valacyclovir is as effective as a 5-day course for the episodic treatment of recurrent genital herpes, with median durations to event end points similar to those for trials described elsewhere . The previously recommended 5-day valacyclovir treatment regimen is based on the results of 2 controlled trials in immunocompetent patients with recurrent genital herpes . The clinical basis of testing a 3-day valacyclovir regimen for episodic treatment of recurrent genital herpes was the previous viral shedding data from a study of 5-day courses of valacyclovir (500 mg b.i.d.) . For HSV culture–positive patients who received a 5-day regimen of valacyclovir, the median time to cessation of viral shedding was 2 days. Thus, it was theorized that maximum effect of valacyclovir on HSV is achievable within the first 3 days of treatment, which is consistent with the mode of action of acyclovir in inhibiting virus replication. Virologic evidence of 3- and 5-day equivalence can be inferred on the basis of a similar trial in Europe , in which 531 patients with recurrent genital herpes were randomized to receive valacyclovir (500 mg b.i.d.) for either 3 or 5 days. The median times to cessation of viral shedding for patients with a positive HSV culture result immediately before starting treatment for 3 or 5 days were similar (1.7 vs. 1.8 days, respectively), which replicates earlier findings .

The results of our study demonstrate that a shorter 3-day treatment course with valacyclovir is clinically equivalent to a 5-day course for the episodic treatment of recurrent genital herpes. In this study, a trend toward longer duration of pain was seen in men who received the shorter course of therapy. Although almost statistically significant, the magnitude of the difference is small and almost certainly not clinically relevant. In clinical situations in which patients exhibit pain as well as other clinical evidence of delayed healing after receiving 3 days of therapy, an additional 2 days of therapy may prove to be beneficial. In addition to the convenience of a shorter course of treatment, a 3-day regimen has the benefit of a 40% decrease in the amount of drug and may result in a 40% reduction in the drug price of a prescription. Whether the patient or insurance company sees a full 40% reduction in prescription price would involve tablet quantity, prescription fees, and other aspects of filling a prescription.

Study Group Members


We thank Mike Colopy for performing statistical analysis.

1 Fleming DT , McQuillan GM , Johnson RE , et al. Herpes simplex virus type 2 in the United States, 1976 to 1994, N Engl J Med, 1997, vol. 337 (pg. 1105-11) 2 Patel R , Tyring S , Strand A , et al. Impact of suppressive antiviral therapy on the health related quality of life of patients with recurrent genital herpes infection, Sex Transm Infect, 1999, vol. 75 (pg. 398-402) 3 Benedetti J , Corey L , Ashley R . Recurrence rates in genital herpes after symptomatic first-episode infection, Ann Intern Med, 1994, vol. 121 (pg. 847-54) 4 Marques AR , Straus SE . Herpes simplex type 2 infections—an update, Adv Intern Med, 2000, vol. 45 (pg. 175-208) 5 Spruance SL , Tyring SK , DeGregorio B , et al. A large-scale, placebo-controlled, dose-ranging trial of peroral valaciclovir for episodic treatment of recurrent herpes genitalis, Arch Intern Med, 1996, vol. 156 (pg. 1729-35) 6 Tyring SK , Douglas JM , Corey L , et al. A randomized placebo-controlled comparison of oral valacyclovir and acyclovir in immunocompetent patients with recurrent genital herpes infections, Arch Dermatol, 1998, vol. 134 (pg. 185-91) 7 Bodsworth NJ , Crooks RJ , Borelli S , et al. Valaciclovir versus aciclovir in patient initiated treatment of recurrent genital herpes: a randomised, double-blind clinical trial, Genitourin Med, 1997, vol. 73 (pg. 110-6) 8 Patel R , Strand A , Crooks RJ . Virological evidence that valaciclovir aborts genital herpes simplex virus lesions . In: Program and abstracts of STIs at the Millennium: Past, Present, and Future (Baltimore), Medical Society for the Study of Venereal Diseases/American Sexually Transmitted Diseases Association (MSSVD/ASTDA), 2000, vol. 15 Members of the study group are listed at the end of the text. Financial support: Glaxo Wellcome (protocol HS2A4004). Presented in part: Eighth International Congress on Infectious Diseases, Boston, May 1998 (abstract 22.012). © 2002 by the Infectious Diseases Society of America

This information from Lexicomp® explains what you need to know about this medication, including what it’s used for, how to take it, its side effects, and when to call your healthcare provider.

Brand Names: US


Brand Names: Canada

What is this drug used for?

  • It is used to treat herpes infections.
  • It is used to treat shingles.
  • It is used to treat cold sores.
  • It is used to treat chickenpox.
  • It may be given to you for other reasons. Talk with the doctor.

What do I need to tell my doctor BEFORE I take this drug?

  • If you are allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.

This drug may interact with other drugs or health problems.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this drug with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take this drug?

  • Tell all of your health care providers that you take this drug. This includes your doctors, nurses, pharmacists, and dentists.
  • Do not take this drug for longer than you were told by your doctor.
  • If you are taking this drug for cold sores, it will not cure cold sores. Talk with your doctor.
  • This drug is not a cure for herpes infections. Talk with the doctor.
  • If you have genital herpes, this drug will not stop it from spreading. Do not have any kind of sex when you have sores or other signs of genital herpes. Genital herpes can also be spread if you do not have any signs. Do not have any kind of sex without using a latex or polyurethane condom. Talk with your doctor.
  • If you are 65 or older, use this drug with care. You could have more side effects.
  • Tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding. You will need to talk about the benefits and risks to you and the baby.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of kidney problems like unable to pass urine, change in how much urine is passed, blood in the urine, or a big weight gain.
  • Feeling confused.
  • Change in the way you act.
  • Mood changes.
  • Hallucinations (seeing or hearing things that are not there).
  • Trouble speaking.
  • Shakiness, trouble moving around, or stiffness.
  • Seizures.
  • Very bad and sometimes deadly blood problems like thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) have happened with this drug in some people. Call your doctor right away if you feel very tired or weak or have any bruising or bleeding; dark urine or yellow skin or eyes; pale skin; change in the amount of urine passed; change in eyesight; change in strength on 1 side is greater than the other, trouble speaking or thinking, or change in balance; or fever.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Headache.
  • Upset stomach or throwing up.
  • Stomach pain.
  • Feeling tired or weak.
  • Period (menstrual) pain.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to your national health agency.

How is this drug best taken?

Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • Take with or without food.
  • Drink lots of noncaffeine liquids unless told to drink less liquid by your doctor.
  • If you are taking this drug to treat cold sores, chickenpox, shingles, or genital herpes, start this drug as soon as you can after your signs start. This drug may not help if you start taking it too late.
  • Keep taking this drug as you have been told by your doctor or other health care provider, even if you feel well.
  • A liquid (suspension) can be made if you cannot swallow pills. Talk with your doctor or pharmacist.

Liquid (suspension):

  • If a liquid (suspension) is made, shake well before use.
  • Measure liquid doses carefully. Use the measuring device that comes with this drug. If there is none, ask the pharmacist for a device to measure this drug.

What do I do if I miss a dose?

  • Take a missed dose as soon as you think about it.
  • If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
  • Do not take 2 doses at the same time or extra doses.

How do I store and/or throw out this drug?


  • Store at room temperature in a dry place. Do not store in a bathroom.

Liquid (suspension):

  • If a liquid (suspension) is made from the tablets, store in a refrigerator. Do not freeze. Throw away any part not used after 28 days.

All products:

  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

General drug facts

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else’s drugs.
  • Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Consumer Information Use and Disclaimer

This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Last Reviewed Date


Valtrex (also known by the generic name Valacyclovir) is a medicine used to treat infections caused by the herpes virus such as chicken pox, shingles, cold sores, and genital sores. Valtrex (Valacyclovir) generic belongs to a group of drugs called antivirals. Valtrex does not cure herpes but rather, it can lessen the effects of the symptoms and prevent the virus from replicating further in the body. It is possible to buy discount Valtrex online from pharmacy.

Taking advantage of cheap Valtrex prices at pharmacy

The next time you need to fill one of your prescriptions, considering filling and purchasing them from an online pharmacy. These pharmacies can offer you a substantial financial savings to your medication bills while offering the same quality and legality of the medications you purchase.

People have begun buying their medicine through online pharmacies. If you have ever looked at some of these online drug stores, you may have noticed that many of the drugs are thirty to eighty percent cheaper in Canada than they are in the United States. The pharmaceutical industry is tightly regulated and prices are controlled by the government, resulting in very cheap, and very affordable prescriptions through online pharmacies. You will find it convenient to order Valtrex online in the comfort and privacy of your home.

What are the side effects of Valtrex (Valacyclovir)?

Side effects associated with the use of Valtrex (Valacyclovir) generic may include

  • headache,
  • fatigue,
  • dizziness,
  • mild nausea,
  • vomiting, or stomach pain,
  • muscle or joint pain,
  • nasal congestion or sore throat.

More severe side effects are possible and may include

  • weakness,
  • fatigue,
  • mood changes,
  • feeling faint,
  • agitation,
  • confusion,
  • feeling shaky,
  • tremors, or seizures,
  • vision or speaking problems,
  • bruising, pale, or yellowing of the skin,
  • problems urinating,
  • shortness of breath,
  • swelling in the limbs or face,
  • sudden weight gain,
  • or pain in your lower back.

Stop using this drug and contact your doctor right away if you experience these or any other unusual symptoms while taking Valtrex.

Allergic reactions are also possible with cheap Valtrex (Valacyclovir) and include

  • a sudden rash,
  • itchiness or swelling of the skin, mouth, or throat,
  • and difficulty breathing.

Contact your doctor immediately if you experience these or any unusual symptoms after using this drug.

What precautions are advised when you buy Valtrex (Valacyclovir)?

Certain medicines could interact with the way cheap Valtrex (Valacyclovir) works in your body. These include other antiviral medicines, non-steroidal anti-inflammatory, immunosuppressants, certain antibiotics, certain cancer drugs, as well as any herbal or nutritional supplements you may be taking. Check with your doctor before you buy Valtrex (Valacyclovir) to avoid a possible drug interaction.

Valtrex (Valacyclovir) generic does not prevent the spread of herpes. Avoid sexual contact or use a condom if engaging in sexual activity.

Women who are pregnant, nursing, or may become pregnant should not buy Valtrex (Valacyclovir) unless specifically prescribed by their doctor.

What happens with an overdose of Valtrex (Valacyclovir)?

Overdose symptoms of Valtrex may cause decreases in urination or not urinating at all. If you suspect you have taken an overdose, contact a doctor immediately.

This summary is not all-inclusive; your pharmacist can provide you with more information about Valtrex (Valacyclovir).

If you want to treat herpes zoster (herpes zoster) you should try to order Valtrex. Numerous clinic studies have shown a great results in people, who buy Valtrex and start treatment. Moreover, ordering Valtrex online you will be able to treat various skin and mucous membranes infections, which are caused by herpes simplex virus, including primary and recurrent genital herpes, as well as to treat labial herpes.

Also, doctors may recommend you to buy Valtrex online for prevention of the development of lesions in recurrent infections that are caused by herpes simplex virus, provided the treatment immediately after the first symptoms of the disease. You can also use cheap Valtrex for reducing transmission of genital herpes in the application of Valtrex as suppressive therapy, as well as to prevent cytomegalovirus infection and disease after organ transplantation.

Generic Valtrex is used for treatment of skin and mucous membranes infections, like herpes.

Commonly, Valtrex dosage for treatment of herpes zoster: 1000mg 3 times a day for 7 days. For treatment of infections caused by herpes simplex virus it is prescribed Valtrex 500mg 2 times a day. For recurrent cases, treatment should last 3 – 5 days. In the primary course of the disease, which may be severe, treatment should be extended to 5-10 days. Treatment should begin as soon as possible. For relapsing forms of infections caused by herpes simplex virus, the ideal would be to use the drug in the prodromal period or immediately after the first symptoms.

Warnings,Generic Valtrex is contraindicated in patients with hypersensitivity to valacyclovir, acyclovir, or to any of Valtrex components.

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