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Foscarnet

    Brands

    DEA Class; Rx

    Common Brand Names; Foscavir, Phosphonoformic acid

    • Antivirals, CMV; 
    • Antivirals, Other

    Antiviral agent; organic analog of inorganic pyrophosphate; not associated with myelosuppression; does not require phosphorylation for activation; used in CMV, herpes simplex, and varicella-zoster.

    Patients with AIDS: Combination therapy with ganciclovir indated for patients who have relapsed following monotherapy with either foscarnet or ganciclovir

    Indicated for Herpes simplex in patients with acyclovir resistance who are immunocompromised

    Hypersensitivity

    • Fever (65%)
    • Nausea (47%)
    • Anemia (33%)
    • Vomiting (33%)
    • Diarrhea (30%)
    • Abnormal renal function/decreased CrCl (27%)
    • Headache (26%)
    • Seizures (10%)
    • Fatigue
    • Depression
    • Confusion
    • Anxiety
    • Dizziness
    • Hypoesthesia
    • Malaise
    • Rash
    • Electrolyte imbalance (especially potassium, calcium, magnesium, and phosphorus)
    • Leukopenia
    • Neutropenia

    Caution with renal impairment

    Do not administer by rapid or bolus IV injection; use infusion pump

    May be associated with changes in serum electrolytes changes including hypocalcemia, hypo- or hyperphosphatemia, hypomagnesemia, or hypokalemia

    Serious acute hypersensitivity reactions (e.g., anaphylactic shock, urticaria, angioedema) reported; if such acute reactions occur, discontinue therapy; and institute appropriate medical therapy immediately

    Cases of status epilepticus reported; several cases of seizures associated with death; electrolyte abnormalities may increase risk of seizures

    Associated with prolongation of QT interval, an ECG abnormality that has been associated with torsades de pointes, reported during postmarketing surveillance; has occurred with confounding risk factors such as underlying cardiac disease, electrolyte abnormalities and other concomitant medications; use caution in patients with history of QT prolongation, taking medications known to prolong the QT interval, patients with electrolyte disturbances, or patients who have other risk factors for QT prolongation; electrocardiograms (ECGs) and measurement of electrolytes should be obtained prior to treatment initiation and periodically during treatment

    Due to sodium content of foscarnet (240 micromoles (5.5 mg) of sodium per mL); avoid foscarnet use when IV infusion of large amount of sodium or water may not be tolerated (e.g. in patients with cardiomyopathy); avoid foscarnet use in patients on a controlled sodium diet

    Pregnancy Category: C

    Lactation: not known if excreted in breast milk, do not nurse

    Adults

    180 mg/kg/day IV.

    Geriatric

    180 mg/kg/day IV.

    Adolescents

    Safety and efficacy have not been established; however, doses up to 180 mg/kg/day IV have been used off-label.

    Children

    Safety and efficacy have not been established; however, doses up to 180 mg/kg/day IV have been used off-label.

    Infants

    Safety and efficacy have not been established; however, doses up to 180 mg/kg/day IV have been used off-label.

    Neonates

    Safety and efficacy have not been established.

    Foscarnet sodium

    injectable solution

    • 2.4g/100mL