Herpes%20simplex%20virus%20infection Treatment

Primary HSV Infection

• If given within 72 hours of symptom onset, antivirals can be effective in reducing severity and duration of symptoms; however, early treatment of primary infection does not prevent recurrences
• Choice of agent depends on cost, dosing schedule and patient preference

Recurrent Genital HSV Infection

• Goals are to treat and prevent symptomatic genital herpes recurrences and preventing transmision to sexual partners by supressing the virus 
• Episodic treatment for recurrent genital HSV disease may be given as a single-day patient-initiated treatment or for 5 days
  • Treatment should be given within the 1st 24 hours of symptoms or during prodromal phase
• 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

Symptomatic Therapy

Analgesics (Oral)

• Eg Ibuprofen, Paracetamol
• Symptomatic relief of pain

Anesthetics (Topical)

• Eg Benzocaine, Dyclonine, viscous Lidocaine
• 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 and inflammation in orolabial HSV disease

Zinc Preparations

• Eg Zinc oxide/glycine cream, Zinc sulfate gel
• Shorten time of resolution of symptoms

Antiviral Therapy - Oral Therapy

Aciclovir

• Acyclic purine nucleoside analogue that is a competitive inhibitor of viral DNA polymerase
• Limits viral replication and stops further spread of the virus to other cells
• Oral and IV are both effective in treating HSV-1 and 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 and is rapidly converted to Penciclovir in gastrointestinal tract (GIT), blood and liver
• Penciclovir has similar mechanism of action as Acyclovir
• Less effective in suppressing viral shedding

Valaciclovir

• L-valine ester prodrug of Aciclovir, rapidly metabolized to Aciclovir by liver and 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 and DNA polymerase
  
  • Foscarnet is virostatic and 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 and HSV which prevents viral entry into cells and 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 with antiviral activity