Herpes simplex 1 and 2 are the viruses that cause oral, genital, central nervous system and other kinds of herpes. Oral and genital herpes usually resolve on their own. Other kinds of herpes are more serious and require treatment to help clear the infection. As of 2010, all FDA-approved treatments for herpes target a viral enzyme called DNA polymerase, which plays a critical role in viral replication. These agents include acyclovir, valacylclovir, famciclovir and ganciclovir.
Acyclovir
Acyclovir is the most common drug used to treat HSV. It is available in intravenous, oral and topical formulations. For serious and life-threatening cases of visceral and central nervous system herpes such as meningitis and encephalitis, intravenous acyclovir is the drug of choice, according to Dr. Lawrence Corey, Chair of Virology at the University of Washington College of Medicine. The major side effect of acyclovir is temporary acute renal insufficiency due to crystallization of the drug in the kidney tissue when the drug is administered intravenously. The risk of renal insufficiency can be reduced if the drug is administered slowly (over one hour) to well-hydrated patients.
Valacyclovir
Valacyclovir, is a oral derivative of acyclovir that is mainly used to treat herpes zoster (shingle) and genital herpes. Compared to acyclovir, it offers better absorption which means that it can be given once a day instead of several times a day for acyclovir. According to Medline Plus, once-daily oral valacyclovir given for one to three days can reduce the likelihood of recurrence of oral-labial herpes and genital herpes (three days). Valacyclovir is also the only antiviral drug that has been proven to reduce the risk of transmission of herpes between sexual partners.
Famciclovir
Famciclovir is an oral drug that is mainly used to treat herpes zoster (shingles) and oral herpes, although, according to Dr. Corey, it has also proven to be clinically effective in the treatment of genital infections due to herpes simplex 1 and 2. For oral herpes (also called cold sores or fever blisters), famciclovir taken as a one-time dose at the start of an outbreak may reduce the severity and duration of symptoms. There is no evidence that famciclovir reduces the risk of transmitting herpes to other people.
Ganciclovir
Ganciclovir is active against both herpes simplex 1 and 2, but its use is usually reserved for eye infections due to a different disease, called cytomegalovirus. As described in Medline Plus, ganciclovir has been associated with bone marrow suppression, a condition in which the bone marrow stops making white blood cells, red blood cells, platelets or all three. People taking ganciclovir who develop other infections, anemia or bleeding problems should contact their physicians right away.
References
- Herpes Simplex Viruses (Chapter); L. Corey; In: Harrison's Principles of Internal Medicine, 17th edition; A.S. Fauci, E. Braunwald, D.L. Kasper, S.L. Hauser, D.L. Longer, J.L. Jameson, and J. Loscalzo (Eds.); 2008
- Medline Plus: Acyclovir
- Medline Plus: Valacyclovir
