Herpes%20simplex%20virus%20infection Treatment
Principles of Therapy
Primary Herpes Simplex Virus (HSV) Infection
- If given within 72 hours of symptom onset, antivirals can be effective in reducing severity & duration of symptoms; however, early treatment of primary infection does not prevent recurrences
- Choice of agent depends on cost, dosing schedule & patient preference
Recurrent Genital Herpes Simplex Virus (HSV) Infection
- Episodic treatment for recurrent genital HSV disease may be given as a single-day patient-initiated treatment or for 5 days
- Long-term suppressive treatment (prophylaxis) for frequent recurrences of genital HSV disease requires at least 3 months to 1 year of therapy to achieve any efficacy
Pharmacotherapy
Symptomatic Therapy
Analgesics (Oral)
- Eg Paracetamol, Ibuprofen
- Symptomatic relief of pain
Anesthetics (Topical)
- Eg Benzocaine, viscous Lidocaine, Dyclonine
- Symptomatic relief of pain
- In theory, may cause sensitization but rarely happens in practice
- Various topical anesthetics are available. Please see prescribing information for specific formulations in the latest MIMS
Oral Preparations
- Symptomatic relief of ulceration & inflammation in orolabial herpes simplex virys (HSV) disease
Zinc Preparations
- Eg Zinc oxide/glycine cream, Zinc sulfate gel
- Shorten time of resolution of symptoms
Antiviral Therapy - Oral
Aciclovir
- Acyclic purine nucleoside analogue that is a competitive inhibitor of viral DNA polymerase
- Limits viral replication & stops further spread of the virus to other cells
- Oral & Intravenous (IV) are both effective in treating HSV-1 & HSV-2
- IV is usually reserved for severe disease or complications where hospitalization is necessary
- Topical agent has limited efficacy for genital HSV, hence not recommended
- Bioavailability is poor requiring frequent dosing
Famciclovir
- Famciclovir is a prodrug of Penciclovir
- Has higher bioavailability than Penciclovir & is rapidly converted to Penciclovir in gastrointestinal tract (GIT), blood & liver
- Penciclovir has similar mechanism of action as Acyclovir
Valaciclovir
- L-valine ester prodrug of Aciclovir, rapidly metabolized to Aciclovir by liver & intestine
- Has better absorption after oral administration than Aciclovir making lower doses or lesser dosing frequency possible
- Has been shown to decrease risk of transmission
Foscarnet
- Pyrophosphate analogue that is a noncompetitive inhibitor of viral RNA & DNA polymerase
- Foscarnet is virostatic & activation by thymidine kinase is not required
- May be used for Aciclovir-resistant mucocutaneous HSV infections in immunocompromised patients
Methisoprinol or Inosiplex
- Antiviral activity by modifying or stimulating cell-mediated immune process
Antiviral Therapy - Topical
Aciclovir - Same as above
- Topical agent has shown limited efficacy
Cidofovir
- May be used for Aciclovir-resistant genital infections
Docosanol
- Inhibits fusion between the cell plasma membrane & HSV which prevents viral entry into cells & viral replication
- Decreases healing time of recurrent herpes labialis
Penciclovir
- Same mechanism of action as Aciclovir
- Decreases healing time of recurrent herpes labialis
Tromantadine
- Derivative of Amantadine w/ antiviral activity