Wednesday, June 19, 2024

Acyclovir Or Valacyclovir For Herpes

How The Intervention Might Work

Valacyclovir Tablets for herpes infections

Antiviral medication is integral to most current treatment guidelines and represents an important pillar in the treatment of herpes zoster ophthalmicus . Acyclovir and valacyclovir have both been approved for the treatment of herpes zoster, and are widely used . Both acyclovir and valacyclovir work by stopping the herpes zoster virus from reproducing and infecting more cells. Inside the cells of the body, acyclovir is phosphorylated specifically by the viral thymidine kinases, and thus selectively activated in those cells that are infected with herpes zoster. After being activated by the addition of phosphate groups, acyclovir is incorporated into the viral deoxyribonucleic acid strand by the enzyme DNA polymerase. Once incorporated, acyclovir acts as a DNA chain terminator. By blocking the action of the viral DNA polymerase, acyclovir prevents the herpes zoster virus from multiplying. This controls the infection and helps the immune system to deal with it.

Is Acyclovir Or Valacyclovir More Effective

Acyclovir and valacyclovir were compared in the treatment of first episodes of genital herpes infections in an international double-blind, randomized trial. Acyclovir was dosed five times daily, and valacyclovir was dosed only twice daily. It found no clinically significant difference in the lesion healing time, duration of pain, or time to loss of all symptoms. Given that, valacyclovir offers the advantage of twice-daily dosing. This decreases pill burden and increases the likelihood that patients will take the regimen as prescribed until completion. Your doctor will determine what is best to treat a genital herpes infection, but twice-daily dosing may offer an advantage for valacyclovir.

In another randomized, double-blind clinical trial, acyclovir and valacyclovir oral tablet doses were compared for a herpes zoster infection, otherwise known as shingles. The results of this study showed valacyclovir significantly accelerated the resolution of pain associated with a shingles rash. While the rash itself resolved in similar times with either treatment regimen, there were fewer ocular complications in those treated with valacyclovir. Another significant advantage for valacyclovir in this study is that it only needed to be dosed three times per day as compared to five times per day for acyclovir. Ultimately, only your prescriber can determine which treatment option is best for you with an active herpes zoster infection.

What Other Drugs Will Affect Acyclovir

Acyclovir can harm your kidneys, especially if you also use certain medicines for infections, cancer, osteoporosis, organ transplant rejection, bowel disorders, high blood pressure, or pain or arthritis .

Other drugs may interact with acyclovir, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

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Valacyclovir Vs Acyclovir: 9 Things That Make Them Different

Valacyclovir and Acyclovir are both antiviral medications, and they both treat HSV-1, HSV-2, and herpes zoster infections.

They are also both pretty similar in their effectiveness against these viruses, and you should expect similar results from the use of either one when taken as directed.

So, just how are these two medications different from one another? There are a few subtle and more noticeable differences between Valacyclovir and Acyclovir that may help guide your doctor and you to prefer one over the other.

Below, we outline 9 differences between Valacyclovir and Acyclovir .

How Do You Take Acyclovir And Valacyclovir

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The dose of both acyclovir and valacyclovir varies depending on your body weight and the condition you are treating. Your healthcare provider will decide what dose is best for you. Oral valacyclovir is more readily available in your body than oral acyclovir. It can be taken once or twice a day, while acyclovir is generally taken up to five times a day.

If you have kidney disease, talk to your doctor about adjusting your acyclovir or valacyclovir dose.

Acyclovir works better if you take it as soon as possible after experiencing symptoms of herpes infection, chickenpox, or shingles. You can take acyclovir with or without meals, but it is best to take the medication with a full glass of water.

You should take valacyclovir within 24 to 48 hours of the onset of symptoms. You can take this medication with or without food. To protect your kidneys, drink extra liquids while you are taking valacyclovir.

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What Are Cold Sores Chickenpox Shingles And Genital Herpes

Cold sores are caused by a herpes virus that may be spread by kissing or other physical contact with the infected area of the skin. They are small, painful ulcers that you get in or around your mouth. It is not known if valacyclovir tablets can stop the spread of cold sores to others.

Chickenpox is caused by a herpes virus called Varicella Zoster Virus . It causes an itchy rash of multiple small, red bumps that look like pimples or insect bites usually appearing first on the abdomen or back and face. It can spread to almost everywhere else on the body and may be accompanied by flu-like symptoms.

Shingles is caused by the same herpes virus that causes chickenpox. It causes small, painful blisters to appear on your skin. Shingles occurs in people who have already had chickenpox. Shingles can be spread to people who have not had chickenpox or the chickenpox vaccine by contact with the infected areas of the skin. It is not known if valacyclovir tablets can stop the spread of shingles to others.

Genital herpes is a sexually transmitted disease. It causes small, painful blisters on your genital area. You can spread genital herpes to others, even when you have no symptoms. If you are sexually active, you can still pass herpes to your partner, even if you are taking valacyclovir tablets. Valacyclovir tablets, taken every day as prescribed and used with the following safer sex practices, can lower the chances of passing genital herpes to your partner.

Can I Use Acyclovir Or Valacyclovir While Pregnant

The acyclovir and valacyclovir pregnancy registries have followed outcomes for fetuses exposed to these drugs in utero. There has been no drug-associated risk of major birth defects in pregnant women. There is insufficient data for a link to miscarriages. There are, however, known risks to untreated HSV infections during pregnancy. Primary herpes infections during the first trimester can cause neonatal chorioretinitis, microcephaly, and skin lesions.

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Why It Is Important To Do This Review

Although it is known that valacyclovir has an improved bioavailability and steadier plasma concentrations, it is currently unclear whether this finally leads to comparable treatment results and less ocular complications. Therefore, an uptodate systematic review is warranted to compare the effects of valacyclovir versus acyclovir for the systemic antiviral treatment of herpes zoster ophthalmicus.

Valacyclovir Lowers Herpes Transmission Rates

Anti-Herpetic Drugs – How They Work

If you have herpes, youve probably taken valacyclovir before as part of an outbreak or initial infection treatment protocol. Valacyclovir is extremely helpful in the management of herpes. During an outbreak, it can speed up the rate of recovery and quickly remove herpes sores.

When it comes to preventing the transmission of herpes, valacyclovir can be helpful but shouldnt be relied on as a 100% effective solution.

Study data shows that people with symptomatic herpes who take valacyclovir are almost 50% less likely to transmit the virus to others than non-medicated people with herpes. In one study, the HSV-2 acquisition rate was reduced from 3.6% to 1.9% using valacyclovir treatment.

Other studies show a similar reduction in herpes transmission rates when the infected person used valacyclovir.

For example, in a 2004 study, researchers noticed that people with non-symptomatic genital herpes were 50% less likely to transfer the virus to their sexual partner. People with herpes symptoms had an even higher drop in transmission ratea reduction of 77 percent.

Its important to remember that this still means there are cases where herpes is transmitted between sexual partners, even when the infected person takes valacyclovir.

In short, while valacyclovir doesnt completely block genital herpes transmission through sex and genital contact, using valacyclovir does lower your risk of catching herpes from a sexual partner.

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How Should I Take Valacyclovir Tablets

  • Take valacyclovir tablets exactly as prescribed by your healthcare provider. Your dose of valacyclovir tablets and length of treatment will depend on the type of herpes infection that you have and any other medical problems that you have.
  • Do not stop valacyclovir tablets or change your treatment without talking to your healthcare provider.
  • Valacyclovir tablets can be taken with or without food.If you are taking valacyclovir tablets to treat cold sores, chickenpox, shingles or genital herpes, you should start treatment as soon as possible after your symptoms start. Valacyclovir tablets may not help you if you start treatment too late.
  • If you miss a dose of valacyclovir tablets, take it as soon as you remember and then take your next dose at its regular time. However, if it is almost time for your next dose, do not take the missed dose. Wait and take the next dose at the regular time.
  • Do not take more than the prescribed number of valacyclovir tablets each day. Call your healthcare provider right away if you take too much valacyclovir tablets.

Drug Interactions Of Acyclovir Vs Valacyclovir

Acyclovir and valacyclovir are known to have negative effects on both the kidneys and the liver. For this reason, both drugs may be dangerous to take with drugs that are also nephrotoxic or hepatotoxic. In some cases, the risk is so severe that the concurrent use with these drugs is contraindicated. This is the case with cidofovir. Other drugs are strongly discouraged from being used concomitantly with acyclovir or valacyclovir for the same concerns. These include capreomycin, foscarnet, and mannitol.

Vaccinations against varicella and zoster have significantly decreased outbreaks of these viruses. However, the administration of live attenuated vaccines depend on the bodys immune system and natural response to the vaccine to produce antibodies in order to be effective. For that reason, acyclovir and valacyclovir should not be administered within a specific window before and after administering these vaccines. Your healthcare provider can provide more specific information prior to your vaccine.

This is not intended to be a comprehensive list of all potential drug interactions. Please ask your doctor or pharmacist for more information and be sure they know all prescription drugs and supplements you are taking prior to beginning antiviral therapy.


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I Already Have An Active Lesion/outbreak Will This Work

Valacyclovir works best when taken at the first signs of an outbreak. For an oral outbreak, this can be when you feel that tingly, itching, blistering or burning in or around the mouth. For a genital outbreak, this can be a fever, body aches, swollen glands, or sores which appear as one or more blisters on or around the mouth, rectum or genitals. Valacyclovir can be used if you already have an outbreak, but it is not as effective as when taken within 24 hours after the first signs of your flare up.

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What Are Warnings And Precautions For Valacyclovir

What are Causes, symptoms &  treatment of Herpes Zoster (Shingles ...


  • This medication contains valacyclovir. Do not take Valtrex if you are allergic to valacyclovir or any ingredients contained in this drug.
  • Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately.


  • Hypersensitivity to valacyclovir or acyclovir

Effects of Drug Abuse

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Valacyclovir Tablets Are Used In Adults:

  • to treat cold sores
  • to treat shingles
  • to treat or control genital herpes outbreaks in adults with normal immune systems
  • to control genital herpes outbreaks in adults infected with the human immunodeficiency virus with CD4 + cell count greater than 100 cells/mm3
  • with safer sex practices to lower the chances of spreading genital herpes to uninfected partners. Even with safer sex practices, it is still possible to spread genital herpes. Valacyclovir tablets used daily with the following safer sex practices can lower the chances of passing genital herpes to your partner.
  • Do not have sexual contact with your partner when you have any symptom or outbreak of genital herpes.
  • Use a condom made of latex or polyurethane whenever you have sexual contact.

Data Collection And Analysis

Selection of studies

Two review authors independently assessed titles and abstracts from the search results and scanned them against the inclusion criteria. Initially, a list was made for included and excluded studies, as well as for studies assessed as unsure. The two review authors then discussed these lists. For potentially relevant studies, the two review authors independently read the fulltext articles to determine whether the articles met the prespecified selection criteria. They discussed disagreements in order to make a final decision if agreement between the two authors was not achieved, a third review author was contacted to reach final consent.

Data extraction and management

Two review authors independently extracted the data of the identified studies , using a prespecified data extraction form. The review authors met to doublecheck all discrepancies if agreement between them was not achieved, a third review author was contacted to reach final consent.

If a publication required translation, the two review authors independently extracted relevant data from the translated article and sought further quality checks from the translator. If there were missing or unclear data, we contacted the corresponding authors twice, at least three months apart, for further information .

In the description of study characteristics, we presented data as reported in the original publications.

Assessment of risk of bias in included studies

Measures of treatment effect

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Valacyclovir And Acyclovir Dosing Is Different

Depending on what is being treated, Acyclovir may be dosed at 200mg to 800mg taken 4-5 times a day.

With Valacyclovir, less frequent dosing is commonly utilized. Depending on the condition, Valacyclovir dosing may be 500mg to 2,000mg 2-3 times daily.

Always use the strengths and dosing schedule prescribed to you by your doctor.

Avoid The Following While You Are Using Acyclovir Buccal Delayed

Acyclovir – Mechanism of Action, Indications, and Side Effects
  • Do not chew gum, touch, or press the buccal tablet after it has been applied.
  • Do not wear upper dentures.
  • Do not brush your teeth until it dissolves. If your teeth need to be cleaned while the tablet is in place, rinse the mouth gently.

Shake the suspension well before each use to mix the medication evenly.

Your symptoms should improve during your treatment with acyclovir. Call your doctor if your symptoms do not improve or if they get worse.

Take or use acyclovir until you finish the prescription, even if you feel better. If you stop taking acyclovir too soon or skip doses, your infection may not be completely treated or may become more difficult to treat. The delayed-release buccal tablet is applied as a one-time dose.

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Treatment For Oral Herpes

The antiviral medications available in pill form have been specifically developed for the treatment of genital herpes. However, it is not uncommon for healthcare providers to prescribe the antiviral drugs to those who have frequent or severe outbreaks of oral herpes.

A recent study found valacyclovir to be effective for treating oral herpes in a one-day treatment of 2 grams taken at the first sign of a cold sore, and then again about 12 hours later.

There are two topical antiviral medications prescribed for the treatment of oral HSV symptoms: acyclovir ointment and penciclovir cream. Both work to speed up the healing process and reduce the viral activity. These topical drugs are put directly on the lesions themselves, but can also be used at the onset of prodrome.

Other topical treatments for oral herpes are available over-the-counter , but are not antiviral compounds like acyclovir and penciclovir. Some also contain ingredients that numb the area and induce temporary relief from the discomfort of an outbreak. Unfortunately, some OTC treatments may actually delay the healing time of symptoms because they can further irritate the area with repeated applications. There is only one OTC FDA-approved cream, called Abreva®, which has been clinically proven to help speed the healing process.

The Virus And Pathogenesis

HSV is a double-stranded DNA virus that may enter the host through abraded skin or intact mucous membranes.1 Epithelial cells are the initial targets. Once infected, these cells die, releasing clear fluid intradermally to form vesicles and merging with other cells to create multinucleated giant cells.

Retrograde transport through adjacent neural tissue to sensory ganglia leads to lifelong latent infection.1 Reactivation of the virus is triggered by local or systemic stimuli such as immunodeficiency, trauma, fever, menstruation, ultraviolet light and sexual intercourse.13 Although emotional stress is assumed to trigger HSV recurrence, recent research fails to show a definite causative role.4 Once reactivated, the virus is transported by the neuron back to the epithelium, where more replication occurs, and another outbreak ensues.

HSV exists as two separate types, labeled 1 and 2, which have affinities for different body sites.2 Ninety percent of infections caused by HSV-2 are genital, and 90 percent of those caused by HSV-1 are oral the reason for this division is unknown.5 In addition, oral HSV-1 infection recurs more frequently than oral HSV-2, and genital HSV-2 recurs more often than genital HSV-1.

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Getting The Most From Your Treatment

  • You should drink plenty while you are on valaciclovir to keep your kidneys working well. Drinking water is best, but hot drinks and non-alcoholic cold drinks are also suitable.
  • Valaciclovir could cause your skin to become more sensitive to sunlight than it is usually. Avoid strong sunlight and sunbeds, and use a sun cream with a high sun protection factor until you know how your skin reacts.
  • If you have been prescribed valaciclovir for genital herpes, do not have sex while you have sores or blisters. Even after these have healed, there is still a small chance that you may pass on the virus when you have sex using a condom reduces this risk.
  • If you are having an operation or any other medical treatment, tell the person carrying out the treatment that you are taking valaciclovir.

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