CIDOFOVIR
| CIDOFOVIR (cye-do'fo-ver) Vistide Classifications: antiviral; Therapeutic: antiviral Prototype: Acyclovir Pregnancy Category: C |
Availability
75 mg/mL injection
Action
Cidofovir, a nucleotide analog, suppresses cytomegalovirus (CMV) replication by inhibiting CMV DNA polymerase.
Therapeutic Effect
Cidofovir reduces the rate of viral DNa synthesis of CMV. It is limited for use in treating CMV retinitis in patients with AIDS. Also effective against herpes viruses and other viruses.
Uses
Treatment of CMV retinitis in patients with AIDS.
Contraindications
Hypersensitivity to cidofovir, history of severe hypersensitivity to probenecid or other sulfa-containing medications; childbearing women and men without barrier contraception; pregnancy (category C); lactation; severe renal dysfunction. Safety and effectiveness in children not established.
Cautious Use
Renal function impairment, history of diabetes, myelosuppression, previous hypersensitivity to other nucleoside analogs; older adults.
Route & Dosage
| CMV Retinitis: Induction & Maintenance Adult: IV 5 mg/kg once weekly for 2 wk. Also give 2 g probenecid 3 h prior to infusion and 1 g 8 h after infusion (4 g total). Continue every 2 wk. Renal Impairment If serum Cr increases by 0.3–0.4, lower dose to 3 mg/kg. |
Administration
- Pretreatment: Prehydrate with IV of 1 L NS infused over 1–2 h immediately before cidofovir infusion. If able to tolerate fluid load, infuse second liter over 1–3 h starting at beginning (or end) of cidofovir infusion.
| Intravenous PREPARE: IV Infusion: Dilute the calculated dose in 100 mL of NS. ADMINISTER: IV Infusion: Give over 1 h at constant rate.
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- Store vials at 20°–25° C (68°–77° F); may store diluted IV solution at 2°–8° C (36°–46° F) for up to 24 h.
Adverse Effects (≥1%)
Body as a Whole: Infection, allergic reactions. GI: Nausea, vomiting, diarrhea. Metabolic: Metabolic acidosis. Hematologic: Neutropenia. CNS: Fever, headache, asthenia. Respiratory: Dyspnea, pneumonia. Special Senses: Ocular hypotony. Urogenital: Nephrotoxicity, proteinuria.Interactions
Drug: aminoglycosides, amphotericin B, foscarnet, pentamidine can increase risk of nephrotoxicity.Pharmacokinetics
Duration: Probenecid increases serum levels and area under concentration–time curve. Elimination: 80–100% in urine; probenecid delays urinary excretion.Nursing Implications
Assessment & Drug Effects
- Evaluate concurrent medications. Nephrotoxic drugs are usually discontinued 7 d prior to starting cidofovir.
- Lab tests: Baseline and periodic serum creatinine, urine protein; periodic and WBC count with differential prior to each dose. Dose adjustments or discontinuation may be required.
- In patients with proteinuria, administer IV hydration and repeat test.
- Periodically monitor visual acuity and intraocular pressure.
- Monitor for S&S of hypersensitivity (see Appendix F). Report their appearance promptly.
Patient & Family Education
- Those taking zidovudine should discontinue or decrease dose to 50% on days of cidofovir administration.
- Initiate or continue regular ophthalmologic exams.
- Be alert to potential adverse reactions caused by probenecid (e.g., headache, nausea, vomiting, hypersensitivity reactions) and cidofovir.
- Closely monitor renal function.
- Women: Use effective contraception during and 1 mo after treatment.
- Men: Use barrier contraception during and 3 mo after treatment.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug