Valtrex vs. Acyclovir: What’s the Difference?

Valtrex is more convenient, because you don’t have to take it as often, but acyclovir costs less per round of treatment.


According to the World Health Organization (WHO), more than two-thirds of the world’s population has the herpes simplex virus 1 (abbreviated HSV-1, and which typically causes oral herpes, or cold sores), and around 11% of the global population has HSV-2, which typically causes genital herpes.

In the United States, the proportions are higher, with around three-fourths of all US residents having HSV-1 and around 22% of the population has HSV-2.

What Is Valtrex?

Valtrex is a name brand drug that is used to treat genital herpes, cold sores, chicken pox, and shingles. It is sold by prescription and is available in 500 mg and 1,000 mg (1 g) dosages. It doesn’t cure herpes, but it stops the spread of the herpes virus in the body by preventing the replication of the DNA that’s needed for the virus to spread. Valtrex is actually what is known as a “prodrug,” which is converted to an active substance called acyclovir once in the body, and this is what is active against the herpes virus.

Important Facts About Valtrex

Valtrex was approved for medical use more than 20 years ago and is used as both a treatment for herpes simplex and as a long-term medication to prevent outbreaks in people who experience repeated episodes of herpes outbreaks. In people who have undergone organ transplantation, it can be used for the prevention of infection by the cytomegalovirus. It can also be used as a protective drug in people whose immune system is compromised, such as people with HIV, or who are undergoing chemotherapy for cancer.

Valtrex Dosage

For an initial genital herpes outbreak, the typical dose is 1 gram (1,000 mg), taken twice a day, for 10 days. For subsequent genital herpes outbreaks, the dosage is usually 500 mg, taken twice a day, for three days. For an initial outbreak of cold sores, 2 g (2,000 mg) is taken every 12 hours for one day, and for shingles, the dose is typically 1 g, taken three times a day for seven days.

When Valtrex is used to treat chicken pox, the dosage must be calculated at 20 mg/kg of body weight, and this amount is taken three times a day for five days. Whatever condition Valtrex is prescribed for, it is most effective when started as early as possible during the course of an outbreak. People who have kidney disease often take a lower dose of Valtrex, because their kidneys are slower at removing the drug from the body, so a normal dose would be too much.

Valtrex is a brand name prescription drug, and therefore it costs more than its generic equivalent, valacyclovir. A 30-day course of Valtrex, 500 mg taken once a day as a preventive measure, will cost from around $370 to around $470.

What Is Acyclovir?

Acyclovir is a generic antiviral drug that can also be used for the treatment of HSV-1, HSV-2, shingles, and chicken pox. It is the generic version of the brand name drug Zovirax. Sometimes it is used as a preventative medicine against a virus called cytomegalovirus. Acyclovir was developed in 1977, and is listed on the WHO’s List of Essential Medicines.

Important Facts About Acyclovir

Like Valtrex, acyclovir does not cure herpes but makes outbreaks less debilitating by preventing the viruses from multiplying and spreading. In people who have the lower immune function, such as people with transplanted organs, people with HIV, or people taking chemotherapy for cancer, acyclovir may be given as a preventative medicine to protect against herpes outbreaks.

Acyclovir Dosage

Otherwise healthy adults taking acyclovir for an initial outbreak of genital herpes usually take 400 mg three times per day, for five to 10 days. For subsequent outbreaks, 400 mg is taken three times per day for five to 14 days. People with shingles usually take 800 mg, five times a day, for seven to 10 days. Adults with chickenpox typically take 800 mg of acyclovir four times a day for five days.

Acycolvir costs less, but must be taken more often and for longer than Valtrex.


Since acyclovir is a generic drug, its costs are lower than the cost of Valtrex. Thirty tablets of acyclovir, 400 mg each, will cost anywhere from around $15 to around $70.

Weighing the Pros and Cons of Each

It’s good to have choices in how to treat herpes virus outbreaks, and Valtrex and acyclovir are two of the most popular choices for this. Each has its own advantages and disadvantages, and it’s up to you to weigh them and determine which fits your needs the best.

The main advantage a person gets from taking Valtrex is its convenience. It lasts longer in the body, so you only have to take it once or twice per day. This can be a big help to people with erratic schedules who are at risk of forgetting to take their medications on time. The main disadvantage of Valtrex is its high cost since it is a name brand drug. Some people, however, feel better about taking branded drugs, and they certainly have this option.

The main advantage a person gets from taking acyclovir is that it is cost-effective. For someone who has repeated outbreaks caused by the herpes virus, costs can add up quickly, and acyclovir makes it more affordable. The main disadvantage of taking acyclovir is that, since it doesn’t last in the body for as long as Valtrex does, it has to be taken more often, and some people have difficulty staying on a multiple-time-per-day medication schedule.

With these drugs, there is also the possibility that one will work better than the other, for whatever reason. Many people may consider trying Valtrex for one outbreak and acyclovir for the next and see if there is any difference in their response. If one offers a better experience and a better quality of life during outbreaks, it may be worthwhile even at a higher financial cost. Ultimately, it’s up to the individual.

Both Valtrex and acyclovir are outstanding drugs, that have improved quality of life for millions of people. While there is no cure for the various herpes viruses, these anti-viral drugs can keep the viruses under control, prevent pain, and help keep the virus from spreading to others when all proper precautions are taken. And today, you can get your prescription medications online, with maximum convenience. We’re happy to show you how.

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