II. Indications

  1. Cytomegalovirus Retinitis (HIV Infection or AIDS)
  2. Other non-FDA approved uses
    1. CMV pneumonitis or Gastroenteritis
    2. Resistant HSV and VZV Infections
    3. Invasive Adenovirus or BK Virus (transplant patients)
    4. In vitro activity against Vaccinia and Variola

III. Contraindications

  1. Serum Creatinine >1.5 mg/dl
  2. eGFR <55 ml/min
  3. Urine Protein > 100 mg/dl (2+ Urine Protein)
  4. Not FDA approved for children

IV. Mechanism

  1. Active against the Herpes Family of Viruses, especially Cytomegalovirus (CMV).
  2. Synthetic, acyclic, monophosphate Nucleotide analog of deoxycytidine (deoxyribonucleoside in DNA synthesis)
    1. Cidofovir is activated within infected host cells, via phosphorylation by pyruvate kinases to Cidofovir diphosphate
    2. Cidofovir diphosphate competes with deoxycytosine-5-triphosphate (dCTP) for viral DNA Polymerase
    3. When incorporated into DNA, it prevents further viral DNA polymerization, and block viral DNA Replication

V. Dosing: Cytomegalovirus Retinitis

  1. Cidofovir for Cytomegalovirus Retinitis
    1. Start: 5 mg/kg IV once weekly for 2 weeks
    2. Next: 5 mg/kg IV every othe week
  2. Medications typically administered with Cidofovir
    1. Probenacid 2 grams orally before and 1 gram orally at 2 and 8 hours after Cidofovir infusion
    2. Normal Saline during Cidofovir infusion

VI. Adverse Effects

  1. Granulocytopenia
  2. Metabolic Acidosis
  3. Ocular adverse effects
    1. Ocular Hypotony
    2. Iritis or Uveitis
  4. Nephrotoxicity (severe)
    1. Similar to Fanconi Syndrome
    2. Stop all other Nephrotoxic Drugs at least 1 week before starting Cidofovir

VII. Safety

  1. Avoid in Lactation
  2. Avoid in Pregnancy due to Teratogenicity (Despite Pregnancy Category C)
    1. Avoid pregnancy for at least one month after taking Cidofovir
    2. Men should use barrier Contraception (Condoms) for at least 3 months after taking Cidofovir

VIII. Labs: Monitoring

  1. Periodic monitoring while on Cidofovir
  2. Neutrophil Count
  3. Intraocular Pressure for hypotony
  4. Renal Function before each Cidofovir dose
    1. Serum Creatinine
    2. Urine Protein

IX. Drug Interactions

  1. Nephrotoxic Drugs
  2. Zidovudine
    1. Hold Zidovudine (or decrease its dose by 50%) on the day Cidofovir is given

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