After acyclovir, the second antiviral for herpes most prescribed is valaciclovir. It is often prescribed under the brand name Valtrex, but it is also available as generic.
In studies, valaciclovir has shown efficacy and safety on par with acyclovir. It is also more easily absorbed in the body than acyclovir, so it does not need to be taken as often. However, a study that focused on six different countries on three continents showed that valaciclovir was prescribed less than half the frequency (20% vs. 46% for acyclovir).
Why could it be? Cost and availability are the most important factors. In the USA, for example, many chain stores such as Wal-Mart, Target, Walgreens and sell generic acyclovir for only $ 4 USD per bottle (30 capsules, 200 mg). Unfortunately, these stores generally do not even offer valaciclovir in its generic version as an alternative. It is available on the RXShopMD.
Another problem is that while the Valtrex brand name seems to be always getting good reviews, valaciclovir in its generic form receives more mixed reviews. While some users report good results, others argue that the number of outbreaks is not reduced when they use it. Some users say that there are differences between each laboratory, with the generic valaciclovir “Teva” you get better results than with the other laboratories.
But, if Valtrex is available at a reasonable price, many will opt for it. While it is recommended that acyclovir be taken twice a day, Valtrex only needs to be taken once a day, either in 500 mg or 1 gram capsules (depending on the frequency of outbreaks). This way, you just have to take a pill in the morning, and forget about viruses for the rest of the day.
Valaciclovir in Clinical Trials
A useful antiviral against the herpes virus (HSV) will do two main things: reduce the frequency of outbreaks and reduce the risk of transmission to uninfected partners. It must also be proven that it is safe (that is, shows low toxicity), with no or minimal side effects. This is how a drug gains approval from the FDA, which valaciclovir has had since December 1995.
Since then, valaciclovir has been studied many times, with positive results. This includes a study from the United Kingdom that was conducted in 1997, which demonstrated the ability of valaciclovir to reduce the number of outbreaks of genital herpes (HSV-2) in patients.
The study involved 382 people, all with a history of recurrent outbreaks frequently (at least 8 per year). They were divided randomly into two groups, one of which received 500 mg of valaciclovir once a day, while the other received a placebo. This went on for 16 weeks.
After this period of time, the results showed that a total of 69% of those who received valaciclovir did not have a single outbreak. In the placebo group, this figure was only 9.5%. When researchers examined safety and side effects, they found that the differences between valaciclovir and placebo were “comparable from adverse experiences to rare and generally mild experiences.”
An even larger study evaluated the ability of valaciclovir to prevent the transmission of genital herpes to an uninfected partner (commonly known as viral spread). This involved 1,484 couples, one of whom was infected with the HSV-2 virus in each pair. They were divided into two groups. A group of 743 people was administered a daily dose of 500 mg of valaciclovir. The other group (741 people) was given a placebo. The duration of the study was 8 months.
The researchers found that administering valaciclovir daily reduced the risk of the virus spreading almost in half. Of the 741 people who had received placebo, 27 had transmitted the genital herpes virus to their partner (3.6%). With valaciclovir, 14 of the 743 had passed the HSV-2 to the couple (1.9%). The researchers concluded that it was a “significant” reduction in the risk of HSV-2 transmission.