USMLE

Cidofovir

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Antivirals
  1. Oseltamivir, Zanamivir
  2. Acyclovir (Famciclovir, Valacyclovir)
  3. Ganciclovir
  4. Foscarnet
  5. Cidofovir
  6. NRTIs
  7. NNRTIs
  8. Integrase Inhibitors
  9. Protease Inhibitors
  10. Entry Inhibitors (Enfuvirtide, Maraviroc)
  11. NS5A Inhibitors
  12. NS5B Inhibitors
  13. NS3/4A Inhibitors

Summary

Cidofovir is an antiviral medication that inhibits viral DNA polymerase. Remember that cidofovir does not require phosphorylation by viral kinases for activation, which means that it is not susceptible to the same resistance mechanisms as acyclovir and ganciclovir. You’ll typically see cidofovir used in the second-line setting to treat patients with HSV or CMV strains that have mutated their viral kinases. Cidofovir is most commonly associated with kidney toxicity.

Key Points

  • Cidofovir
    • Mechanism
      • Viral DNA polymerase inhibitor
        • Analog of cytidine monophosphate, which impairs chain elongation by DNA polymerase
      • Requires phosphorylation but does not require viral kinase
        • Uses cellular kinases, but not viral kinases, for conversion into active triphosphate form
        • Can treat viral strains with mutated or downregulated viral kinase
      • Long-half life
    • Clinical Use
      • HSV
        • Especially in immunocompromised patients with kinase-mutated viral strains resistant to treatment by acyclovir
        • Foscarnet may also be used in this setting
      • CMV
        • Especially in immunocompromised patients with CMV retinitis and colitis with kinase-mutated viral strains resistant to treatment by ganciclovir
        • Foscarnet may also be used in this setting
    • Adverse Effects
      • Nephrotoxic
        • Administer probenecid and hydrate/IV saline to reduce toxicity