Medical term:

Vistide


cidofovir

Vistide

Pharmacologic class: Purine nucleotide cytosine analog

Therapeutic class: Antiviral

Pregnancy risk category C

Action

Exerts antiviral effect by interfering with DNA synthesis of CMV, thereby inhibiting viral replication

Availability

Solution for injection: 75 mg/ml in 5-ml, single-use vials

Indications and dosages

➣ CMV retinitis in AIDS patients

Adults: 5 mg/kg I.V. infused over 1 hour q week for 2 continuous weeks; then 5 mg/kg I.V. once q 2 weeks as a maintenance dose

Dosage adjustment

• Renal impairment

Contraindications

• Hypersensitivity to drug, probenecid, or other sulfa-containing agents

• Creatinine level above 1.5 mg/dl, calculated creatinine clearance of 55 ml/minute or less, or urine protein level of 100 mg/dl or higher

• Concurrent use of nephrotoxic drugs

Precautions

Use cautiously in:

• renal impairment

• elderly patients

• pregnant or breastfeeding patients

• children younger than age 12 (safety and efficacy not established).

Administration

☞ Be aware that drug carries a high risk of nephrotoxicity. Follow administration instructions carefully, including preinfusion and postinfusion hydration with I.V. normal saline solution.

• Premedicate with probenecid 2 g P.O., as prescribed, 3 hours before starting cidofovir infusion.

• Before starting infusion, give 1 L of normal saline solution over 1 to 2 hours.

• Mix I.V. dose in 100 ml of normal saline solution and infuse over 1 hour using infusion pump.

• Give 1 L of normal saline solution during or immediately after cidofovir infusion (unless contraindicated).

• Administer probenecid 1 g 2 hours and 8 hours after infusion ends, as prescribed.

☞ If drug touches skin, flush thoroughly with water.

Adverse reactions

CNS: headache, seizures, coma

EENT: decreased intraocular pressure

GI: nausea, vomiting, diarrhea, anorexia, oral candidiasis

GU: proteinuria, nephrotoxicity

Hematologic: neutropenia

Hepatic: hepatomegaly

Metabolic: metabolic acidosis

Musculoskeletal: muscle contractions

Respiratory: dyspnea, increased cough

Skin: rash, alopecia

Other: pain, fever, chills, infection, pain at I.V. site

Interactions

Drug-drug. Nephrotoxic drugs: increased risk of nephrotoxicity

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, blood urea nitrogen, creatinine, lactate dehydrogenase: increased values

Bicarbonate, creatinine clearance, hemoglobin, neutrophils, platelets: decreased values

Patient monitoring

• Assess white blood cell count and creatinine and urine protein levels within 48 hours of each dose.

• Closely monitor intraocular pressure and visual acuity.

• Monitor hepatic enzyme levels in patients with hepatic disease.

Patient teaching

☞ Tell patient to immediately report fever, vision changes, nausea, vomiting, rash, or urinary output changes.

• Instruct patient to take probenecid, as prescribed, before each dose and to have regular eye examinations.

• Urge female patient of childbearing age to use effective contraception during and for 1 month after therapy.

• Instruct male patients to use barrier contraception during and for 3 months after therapy.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved

cidofovir

(sye-doe-foe-veer) ,

Vistide

(trade name)

Classification

Therapeutic: antivirals
Pregnancy Category: C

Indications

Management of cytomegalovirus (CMV) retinitis in HIV-infected patients (with probenecid).

Action

Suppresses replication of CMV by inhibiting viral DNA synthesis.

Therapeutic effects

Slows progression of CMV retinitis; may not be curative.

Pharmacokinetics

Absorption: IV administration results in complete bioavailability.
Distribution: Unknown.
Metabolism and Excretion: Excreted mostly unchanged by the kidneys.
Half-life: Unknown.

Time/action profile

ROUTEONSETPEAKDURATION
IVrapidend of infusionunknown

Contraindications/Precautions

Contraindicated in: Hypersensitivity to cidofovir, probenecid, or sulfonamides;Serum Cr >1.5 mg/dL, CCr ≤55 mL/min, or urine protein ≥100 mg/dL (≥2+ proteinuria);Concurrent use of foscarnet, amphotericin B, aminoglycoside anti-infectives, NSAIDs, or IV pentamidine.
Use Cautiously in: Obstetric / Pediatric: Safety not established; Lactation: Breast feeding is not recommended in HIV-positive patients
Exercise Extreme Caution in: Any condition or medication that ↑ the risk of dehydration.

Adverse Reactions/Side Effects

Central nervous system

  • headache (most frequent)
  • weakness (most frequent)

Ear, Eye, Nose, Throat

  • ↓ intraocular pressure
  • hearing loss
  • iritis
  • ocular hypotony
  • uveitis

Respiratory

  • dyspnea (most frequent)
  • pneumonia

Gastrointestinal

  • hepatotoxicity (life-threatening)
  • pancreatitis (life-threatening)
  • abdominal pain (most frequent)
  • nausea (most frequent)
  • vomiting (most frequent)
  • anorexia
  • diarrhea

Genitourinary

  • renal failure (life-threatening)
  • proteinuria (most frequent)

Dermatologic

  • alopecia (most frequent)
  • rash (most frequent)

Fluid and Electrolyte

  • ↓ serum bicarbonate

Hematologic

  • neutropenia (most frequent)
  • anemia

Metabolic

  • metabolic acidosis (life-threatening)

Miscellaneous

  • chills (most frequent)
  • fever (most frequent)
  • infection (most frequent)

Interactions

Drug-Drug interaction

↑ risk of nephrotoxicity with aminoglycosides, amphotericin B, foscarnet, and pentamidine and should be avoided; wait 7 days after giving other nephrotoxic agents.Probenecid, which is required concurrently, may interact with acetaminophen, acyclovir, ACE inhibitors, barbiturates, benzodiazepines, bumetanide, methotrexate, famotidine, furosemide, NSAIDs, theophylline, and zidovudine.

Route/Dosage

Intravenous (Adults) 5 mg/kg once weekly for 2 wk, followed by 5 mg/kg every 2 wk (must be given with probenecid).

Renal Impairment

Intravenous (Adults) ↑ in serum creatinine of 0.3–0.4 mg/dL—↓ dose to 3 mg/kg; discontinue if serum creatinine ↑ ≥0.5 mg/dL over baseline.

Availability (generic available)

Solution for injection: 75 mg/mL

Nursing implications

Nursing assessment

  • Monitor vision for progression of CMV retinitis. Monitor ocular symptoms, intraocular pressure, and visual acuity periodically.
  • Antiemetics and administration after a meal may minimize nausea and vomiting associated with probenecid. If allergic reactions occur in association with probenecid, pretreatment with antihistamines or acetaminophen should be considered.
  • Monitor vital signs periodically. May cause fever, hypotension, and tachycardia. Monitor patients for early signs and symptoms of infection.
  • Lab Test Considerations: Renal function, measured by serum Cr and urine protein, must be monitored within 48 hr before each dose and throughout cidofovir therapy. In patients with proteinuria, administer IV hydration and repeat urine protein test. If renal function deteriorates, dose modification or temporary discontinuation should be considered.
    • Monitor WBC before each dose. Granulocytopenia may occur.
    • May cause hyperglycemia, hyperlipemia, hypocalcemia, hypokalemia, and elevated alkaline phosphatase, AST, and ALT.

Potential Nursing Diagnoses

Risk for infection (Indications)

Implementation

  • Probenecid and saline prehydration must be given with cidofovir to minimize renal toxicity. Probenecid must be administered 2 g orally given 3 hr before, then 1 g given 2 hr and 8 hr after completion of cidofovir infusion. Saline prehydration with 1 L of 0.9% NaCl must be given over 1–2 hr before cidofovir. A second liter over 1–3 hr is recommended concurrently with or after cidofovir.
    • Patients receiving foscarnet, amphotericin B, aminoglycoside, NSAIDs, or IV pentamidine should wait at least 7 days after these agents to begin cidofovir.
  • Intravenous Administration
  • pH: 6.7–7.6.
  • Intermittent Infusion: Diluent: Dilute in 100 mL of 0.9% NaCl. Solution is stable for 24 hr if refrigerated. Allow refrigerated solution to return to room temperature before administration.
  • Rate: Administer over 1 hr.
  • Additive Incompatibility: Information unavailable. Do not admix with other solutions or medications.

Patient/Family Teaching

  • Inform patient that cidofovir is not a cure for CMV retinitis and that retinitis may continue to progress during and after therapy.
  • Inform patient that concurrent antiretroviral therapy may be continued. However, zidovudine therapy should be temporarily discontinued or decreased by 50% on the days of cidofovir therapy because of the effects of probenicid on zidovudine.
  • Advise patient of the possibility of renal toxicity from cidofovir. Emphasize the importance of routine lab tests to monitor renal function.
  • Discuss with patient the possibility of hair loss. Explore coping strategies.
  • Advise patients to have routine ophthalmologic exams after cidofovir therapy.
  • Inform patient that cidofovir may have teratogenic effects. Women should use contraception during and for 1 mo after therapy. Men should use barrier contraception during and for 3 mo after therapy.

Evaluation/Desired Outcomes

  • Decrease in symptoms and arrest of progression of CMV retinitis in HIV-infected patients.
Drug Guide, © 2015 Farlex and Partners

Vistide®

Cidofovir, see there.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

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