Foscarnet

Foscarnet 

  • Pregnancy Category C

Formulations

  • Topical as 1% and 3% cream, intravenous 

Dosing 

Acyclovir-resistant herpes simplex virus “HSV” (immunocompromised)

  • 40 mg/kg IV every 8–12 hours for 2–3 weeks or until lesion resolution
  • Considered treatment of choice for Acyclovir-resistant HSV

  • Pyrophosphate analog, inhibits activity of pyrophosphate binding site on virus specific DNA polymerase and reverse transcriptase; importantly, does NOT depend on viral thymidine kinase

  • Active against all HHV (including Cytomegalovirus (CMV) – often used in setting of immunocompromised host for CMV infection)

Topical

  • Local skin reactions

Intravenous

  • Renal toxicity, anemia, erosive penile lesions, gastrointestinal side effects, electrolyte imbalance, seizures, thrombophlebitis and deep vein thrombosis

* For further reading refer to a pharmacology source

Importantly, does NOT depend on viral thymidine kinase for phosphorylation