Acyclovir, Famciclovir & Valacyclovir

Medical Reviewer

Antiviral medications have proven clinical effectiveness against genital herpes. In this sharepost I provide a snapshot of the three most commonly prescribed medications; Acyclovir (Zovirax), Famciclovir (Famvir) and Valacyclovir (Valtrex).

Acyclovir helps to prevent the herpes virus from spreading to other cells. It is used in the treatment of genital herpes, but also chickenpox and shingles. Acyclovir is available as tablets, capsules, an ointment, a suspension or as an injection. In ointment form it may be applied directly to the affected area. This is known to reduce pain, help limit the spread of infection and speed up the healing process. During the first outbreak of genital herpes a typical prescription is along the lines of tablets or capsules, 400 mg, three times a day for up to 10 days. This may vary slightly. Acyclovir may also be used in cases of recurrent outbreaks and, where more than six outbreaks occur in a year, it can be taken daily.

Famciclovir  also helps to prevent the herpes virus from spreading to other cells. Like acyclovir it does not cure or prevent the spread of herpes. Famciclovir is available as a tablet for the treatment of cold sores (herpes simplex 1) and genital herpes (herpes simplex 2). Its action is broadly similar to Acyclovir in that it helps to relieve itching, burning and pain and speeds up the healing time. Because it has a longer therapeutic effect than acyclovir it can be taken fewer times a day.

Valacyclovir is classed as a prodrug. When taken, valacyclovir is converted to acyclovir in the body. Valacyclovir is available as a cream or in oral or intravenous forms. It has a longer therapeutic duration than acyclovir and can therefore be taken fewer times a day.

Side Effects
are similar for all three forms of medication. The most common are headaches, nausea or vomiting. These tend to be short lived and the effects pass after a few days. Less common side effects include dizziness, abdominal pain, diarrhea, skin rash or weakness.

CDC. Sexually Transmitted Diseases Treatment Guidelines, 2006.
Oqbru, O (2008) Accessed 05/08/2009