II. Indications
- Cytomegalovirus Retinitis (HIV Infection or AIDS)
- Other non-FDA approved uses
- CMV pneumonitis or Gastroenteritis
- Resistant HSV and VZV Infections
- Invasive Adenovirus or BK Virus (transplant patients)
- In vitro activity against Vaccinia and Variola
III. Contraindications
- Serum Creatinine >1.5 mg/dl
- eGFR <55 ml/min
- Urine Protein > 100 mg/dl (2+ Urine Protein)
- Not FDA approved for children
IV. Mechanism
- Active against the Herpes Family of Viruses, especially Cytomegalovirus (CMV).
- Synthetic, acyclic, monophosphate Nucleotide analog of deoxycytidine (deoxyribonucleoside in DNA synthesis)
- Cidofovir is activated within infected host cells, via phosphorylation by pyruvate kinases to Cidofovir diphosphate
- Cidofovir diphosphate competes with deoxycytosine-5-triphosphate (dCTP) for viral DNA Polymerase
- When incorporated into DNA, it prevents further viral DNA polymerization, and block viral DNA Replication
V. Dosing: Cytomegalovirus Retinitis
- Cidofovir for Cytomegalovirus Retinitis
- Start: 5 mg/kg IV once weekly for 2 weeks
- Next: 5 mg/kg IV every othe week
- Medications typically administered with Cidofovir
- Probenacid 2 grams orally before and 1 gram orally at 2 and 8 hours after Cidofovir infusion
- Normal Saline during Cidofovir infusion
VI. Adverse Effects
- Granulocytopenia
- Metabolic Acidosis
- Ocular adverse effects
- Nephrotoxicity (severe)
- Similar to Fanconi Syndrome
- Stop all other Nephrotoxic Drugs at least 1 week before starting Cidofovir
VII. Safety
- Avoid in Lactation
- Avoid in Pregnancy due to Teratogenicity (Despite Pregnancy Category C)
- Avoid pregnancy for at least one month after taking Cidofovir
- Men should use barrier Contraception (Condoms) for at least 3 months after taking Cidofovir
VIII. Labs: Monitoring
- Periodic monitoring while on Cidofovir
- Neutrophil Count
- Intraocular Pressure for hypotony
- Renal Function before each Cidofovir dose
IX. Drug Interactions
- Nephrotoxic Drugs
-
Zidovudine
- Hold Zidovudine (or decrease its dose by 50%) on the day Cidofovir is given