VISTIDE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for VISTIDE (VISTIDE).

How it works

Cidofovir is a nucleotide analogue that inhibits viral DNA polymerase by incorporating into viral DNA and causing chain termination, with selectivity for cytomegalovirus (CMV) DNA polymerase.

What the body does with it

Metabolism	Minimal hepatic metabolism; primarily excreted unchanged in the urine via renal tubular secretion and glomerular filtration.
Excretion	Primarily renal excretion via glomerular filtration and active tubular secretion. Approximately 90-95% of the dose is excreted unchanged in the urine within 24 hours. Biliary/fecal excretion accounts for <5%.
Half-life	Terminal elimination half-life is approximately 1.5-2 hours in patients with normal renal function. In patients with renal impairment, the half-life can extend to 5-10 hours or longer, necessitating dose adjustment based on creatinine clearance.
Protein binding	Less than 5% bound to plasma proteins. Binding is negligible and not clinically significant.
Volume of Distribution	Steady-state volume of distribution is approximately 0.3-0.5 L/kg, indicating distribution primarily into extracellular fluid and tissues, but limited intracellular accumulation except in renal tubules.
Bioavailability	Intravenous route only; oral bioavailability is negligible (<5%) due to poor gastrointestinal absorption. Not administered orally.
Onset of Action	Intravenous infusion: Clinical antiviral effect typically observed within 1-2 days, with reduction in CMV DNA levels measurable after 1-3 doses.
Duration of Action	Antiviral effect persists for 1-2 weeks after a single dose due to prolonged intracellular active metabolite (cidofovir diphosphate) with a half-life of 30-100 hours. However, dosing interval is typically every other week due to nephrotoxicity concerns.

Classification & Brands

Dosing & administration

5 mg/kg intravenously once weekly for 2 consecutive weeks, then every other week thereafter.

Dosage form	SOLUTION
Renal impairment	Contraindicated in patients with serum creatinine >1.5 mg/dL, creatinine clearance ≤55 mL/min, or urine protein ≥100 mg/dL. No dose adjustment is recommended; if renal function deteriorates to these levels during therapy, discontinue VISTIDE.
Liver impairment	No specific adjustments provided for hepatic impairment. Use with caution in patients with hepatic dysfunction.
Pediatric use	Safety and efficacy not established in pediatric patients.
Geriatric use	No specific geriatric dose adjustments; use with caution due to age-related renal function decline.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for VISTIDE (VISTIDE).

Breastfeeding	It is unknown whether cidofovir is excreted in human breast milk. Due to potential for serious adverse reactions in nursing infants, breastfeeding should be discontinued during therapy. M/P ratio is not available.
Teratogenic Risk	Cidofovir is embryotoxic and teratogenic in animal studies. In pregnant women, use only if benefit outweighs risk. First trimester: avoid unless essential; may cause developmental abnormalities. Second and third trimesters: limited data; potential for fetal nephrotoxicity and ototoxicity. Should be used with extreme caution.

Warnings & precautions

■ FDA Black Box Warning

Renal impairment: Cidofovir is nephrotoxic and can lead to acute renal failure. Dose adjustment, hydration, and probenecid co-administration are required. Neutropenia: May cause severe neutropenia. Contraindicated in patients with pre-existing severe renal impairment (serum creatinine >1.5 mg/dL, creatinine clearance ≤55 mL/min, or urine protein ≥100 mg/dL).

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to cidofovir; severe renal impairment (serum creatinine >1.5 mg/dL, creatinine clearance ≤55 mL/min, or urine protein ≥100 mg/dL); concurrent use with other nephrotoxic agents; history of clinically significant neutropenia.

Clinical Precautions

Precautions

Renal toxicity: Monitor renal function (serum creatinine, urine protein) before each dose; use with probenecid and hydration. Neutropenia: Monitor neutrophil counts. Ocular toxicity: May cause iritis, uveitis, or hypotony. Carcinogenicity: Potential for carcinogenesis in animals. Use in pregnancy: Category C; avoid unless benefit outweighs risk.

Clinical Tips & Counseling

Drug interactions

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VISTIDE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for VISTIDE (VISTIDE).

How it works

Cidofovir is a nucleotide analogue that inhibits viral DNA polymerase by incorporating into viral DNA and causing chain termination, with selectivity for cytomegalovirus (CMV) DNA polymerase.

What the body does with it

Metabolism	Minimal hepatic metabolism; primarily excreted unchanged in the urine via renal tubular secretion and glomerular filtration.
Excretion	Primarily renal excretion via glomerular filtration and active tubular secretion. Approximately 90-95% of the dose is excreted unchanged in the urine within 24 hours. Biliary/fecal excretion accounts for <5%.
Half-life	Terminal elimination half-life is approximately 1.5-2 hours in patients with normal renal function. In patients with renal impairment, the half-life can extend to 5-10 hours or longer, necessitating dose adjustment based on creatinine clearance.
Protein binding	Less than 5% bound to plasma proteins. Binding is negligible and not clinically significant.
Volume of Distribution	Steady-state volume of distribution is approximately 0.3-0.5 L/kg, indicating distribution primarily into extracellular fluid and tissues, but limited intracellular accumulation except in renal tubules.
Bioavailability	Intravenous route only; oral bioavailability is negligible (<5%) due to poor gastrointestinal absorption. Not administered orally.
Onset of Action	Intravenous infusion: Clinical antiviral effect typically observed within 1-2 days, with reduction in CMV DNA levels measurable after 1-3 doses.
Duration of Action	Antiviral effect persists for 1-2 weeks after a single dose due to prolonged intracellular active metabolite (cidofovir diphosphate) with a half-life of 30-100 hours. However, dosing interval is typically every other week due to nephrotoxicity concerns.

Classification & Brands

Dosing & administration

5 mg/kg intravenously once weekly for 2 consecutive weeks, then every other week thereafter.

Dosage form	SOLUTION
Renal impairment	Contraindicated in patients with serum creatinine >1.5 mg/dL, creatinine clearance ≤55 mL/min, or urine protein ≥100 mg/dL. No dose adjustment is recommended; if renal function deteriorates to these levels during therapy, discontinue VISTIDE.
Liver impairment	No specific adjustments provided for hepatic impairment. Use with caution in patients with hepatic dysfunction.
Pediatric use	Safety and efficacy not established in pediatric patients.
Geriatric use	No specific geriatric dose adjustments; use with caution due to age-related renal function decline.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for VISTIDE (VISTIDE).

Breastfeeding	It is unknown whether cidofovir is excreted in human breast milk. Due to potential for serious adverse reactions in nursing infants, breastfeeding should be discontinued during therapy. M/P ratio is not available.
Teratogenic Risk	Cidofovir is embryotoxic and teratogenic in animal studies. In pregnant women, use only if benefit outweighs risk. First trimester: avoid unless essential; may cause developmental abnormalities. Second and third trimesters: limited data; potential for fetal nephrotoxicity and ototoxicity. Should be used with extreme caution.