Herpes simplex virus has multiple strains causing a multitude of different diseases. Most people are familiar with herpes simplex-1 virus (HSV-1), the viral strain associated with cold sores. The other familiar strain of the herpes simplex virus is HSV-2, the strain associated with genital herpes. The patient presentation, the strain and the disease will determine which medication is necessary for treatment.
Acyclovir
Acyclovir decreases outbreaks by interrupting the replication process of the virus. It interferes with DNA by interrupting an enzyme that the virus needs to create new viral organisms. Acyclovir is indicated to treat both HSV-1 and HSV-2. It is used both for an initial outbreak, and to prevent and manage ongoing outbreaks. Side effects include nausea and vomiting. Other side effects, seen when treating cases of herpes-related encephalitis or meningitis, include phlebitis, renal dysfunction, and, rarely, lethargy, confusion, seizures and coma, according to Merck.
Valacyclovir
Valacyclovir is another drug that can be used for genital herpes (HSV-2) outbreaks. However, unlike acyclovir, it does not prevent outbreaks. It simply contains the current outbreak. Like other antiviral drugs, valacyclovir inhibits DNA synthesis. Valacyclovir does this by inactivating DNA viral polymerase, an enzyme associated with the herpes virus. Valacyclovir is less effective against HSV than acyclovir. Valacyclovir has the same indications as acyclovir. Gastrointestinal symptoms, blood disorders and renal impairment are the most reported adverse effects associated with valacyclovir.
Foscarnet
When treating acyclovir-resistant viruses, doctors use other drugs. One such drug is foscarnet. Foscarnet is used against both HSV-1 and HSV-2. Foscarnet works by a different mechanism to inhibit viral replication through DNA disturbance. Foscarnet's reported side effects include renal impairment, which is a serious side effect seen with the drug. Therefore, those with renal disease should avoid or use with caution. Electrolyte disturbances, seizure activity, fever and anemia are associated with foscarnet.
Trifluridine
Trifluridine is indicated to treat HSV-1 and HSV-2. Trifluridine works by interfering with DNA synthesis. Trifluiridine is used topically for ophthalmologic cases of herpes because it penetrates the intraocular cavity effectively. It is used when other topical agents fail. Mild burning and stinging were most commonly seen in a small percentage of patients, as reported by the National Institutes of Health (NIH).
