section name header

Pronunciation ⬇

foss-KAR-net

Classifications ⬆ ⬇

Therapeutic Classification: antivirals

Indications ⬆ ⬇

REMS

Action ⬆ ⬇

  • Prevents viral replication by inhibiting viral DNA polymerase and reverse transcriptase.
Therapeutic effects:
  • Virustatic action against susceptible viruses, including CMV.

Pharmacokinetics ⬆ ⬇

Absorption: IV administration results in complete bioavailability.

Distribution: Variable penetration into CSF. May concentrate in and be slowly released from bone.

Metabolism/Excretion: 80–90% excreted unchanged in urine.

Half-Life: 3 hr (normal renal function); longer half-life of 90 hr may reflect release of drug from bone.

Time/Action Profile ⬆ ⬇

ROUTEONSETPEAKDURATION
IVrapidend of infusion8–24 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

  • Hypersensitivity;
  • HF (due to sodium content);
  • Patients on sodium-restricted diets;
  • Hemodialysis;
  • Lactation: Lactation.

Use Cautiously in:

  • Renal impairment (dose ↓ required if CCr ≤1.4 mL/min/kg);
  • Seizure disorders;
  • QT interval prolongation or cardiovascular disease;
  • Hypokalemia or hypomagnesemia (must be corrected prior to therapy);
  • OB: Safety not established in pregnancy;
  • Pedi: Safety and effectiveness not established in children.

Adv. Reactions/Side Effects ⬆ ⬇

CV: chest pain, edema, palpitations, QT interval prolongation, TORSADES DE POINTES

Derm: ↑sweating, pruritus, rash, skin ulceration

EENT: conjunctivitis, eye pain, vision abnormalities

F and E: hypocalcemia, hypokalemia, hypomagnesemia, hyperphosphatemia, hypophosphatemia

GI: diarrhea, nausea, vomiting, abdominal pain, abnormal taste sensation, anorexia, constipation, dyspepsia

GU: RENAL FAILURE, albuminuria, dysuria, nocturia, polyuria, urinary retention

Hemat: anemia, leukopenia, neutropenia

Local: pain/inflammation at injection site

MS: arthralgia, myalgia, back pain, involuntary muscle contraction

Neuro: headache, anxiety, ataxia, confusion, depression, dizziness, fatigue, hypoesthesia, neuropathy, paresthesia, SEIZURES, tremor, weakness

Resp: cough, dyspnea

Misc: fever, chills, flu-like syndrome, HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS, URTICARIA, AND ANGIOEDEMA), MALIGNANCY

Interactions ⬆ ⬇

Drug-drug:

Route/Dosage ⬆ ⬇

Cytomegalovirus Retinitis

  • IV (Adults ): 60 mg/kg every 8 hr or 90 mg/kg every 12 hr for 2–3 wk as induction therapy; then 90–120 mg/kg once daily as maintenance therapy.

Renal Impairment

  • IV (Adults ): CCr >1–1.4 mL/min/kg: 45 mg/kg every 8 hr or 70 mg/kg every 12 hr for 2–3 wk as induction therapy; then 70–90 mg/kg once daily as maintenance therapy; CCr >0.8–1 mL/min/kg: 50 mg/kg every 12 hr for 2–3 wk as induction therapy; then 50–65 mg/kg once daily as maintenance therapy; CCr >0.6–0.8 mL/min/kg: 40 mg/kg every 12 hr or 80 mg/kg once daily for 2–3 wk as induction therapy; then 80–105 mg/kg every 48 hr as maintenance therapy; CCr >0.5–0.6 mL/min/kg: 60 mg/kg once daily for 2–3 wk as induction therapy; then 60–80 mg/kg every 48 hr as maintenance therapy; CCr >0.4–0.5 mL/min/kg: 50 mg/kg once daily for 2–3 wk as induction therapy; then 50–65 mg/kg every 48 hr as maintenance therapy; CCr <0.4 mL/min/kg: Not recommended.

Herpes Simplex Virus

  • IV (Adults ): 40 mg/kg every 8–12 hr for 2–3 wk or until healing occurs.

Renal Impairment

  • IV (Adults ): CCr >1–1.4 mL/min/kg: 30 mg/kg every 8–12 hr for 2–3 wk or until healing occurs; CCr >0.8–1 mL/min/kg: 20–35 mg/kg every 8–12 hr for 2–3 wk or until healing occurs; CCr >0.6–0.8 mL/min/kg: 25 mg/kg every 12 hr or 35 mg/kg once daily for 2–3 wk or until healing occurs; CCr >0.5–0.6 mL/min/kg: 25–40 mg/kg once daily for 2–3 wk or until healing occurs; CCr >0.4–0.5 mL/min/kg: 20–35 mg/kg once daily for 2–3 wk or until healing occurs; CCr <0.4 mL/min/kg: Not recommended.

Availability ⬆ ⬇

(Generic available)
  • Solution for injection: 24 mg/mL

Assessment ⬆ ⬇

  • Monitor ECG periodically during therapy for QT interval prolongation and arrhythmias.
  • CMV Retinitis: Diagnosis of CMV retinitis should be determined by ophthalmoscopy before treatment with foscarnet. Ophthalmologic examinations should be performed at the conclusion of induction and every 4 wk during maintenance therapy.
  • Culture for CMV (urine, blood, throat) may be taken before administration, but a negative CMV culture does not rule out CMV retinitis.
  • HSV Infections: Assess lesions before and daily during therapy.
  • Monitor for seizure activity. Implement seizure precautions if necessary.
  • Assess for hypersensitivity reactions (anaphylaxis, urticaria, angioedema). Implement supportive medical treatment (epinephrine) as indicated.

Lab Test Considerations:

  • Monitor serum creatinine before and 2–3 times weekly during induction therapy and at least once every 1–2 wk during maintenance therapy. Monitor 24-hr CCr before and periodically throughout therapy. If CCr drops below 0.4 mL/min/kg, discontinue foscarnet.
    • Monitor serum calcium, magnesium, potassium, and phosphorus before and 2–3 times weekly during induction therapy and at least weekly during maintenance therapy. May cause hypocalcemia, hypomagnesemia, hypokalemia, and hypophosphatemia.
    • May cause anemia, granulocytopenia, leukopenia, and thrombocytopenia. May cause ↑ AST and ALT levels and abnormal A-G ratios.

Implementation ⬆ ⬇

  • Adequately hydrate patient with 750–1000 mL of 0.9% NaCl or D5W before 1st infusion to establish diuresis; then administer 750–1000 mL with 120 mg/kg of foscarnet or 500 mL with 40–60 mg/kg of foscarnet with each dose to prevent renal toxicity.

IV Administration:

  • Intermittent Infusion: Diluent: May be administered via central line undiluted. If administered via peripheral line, must be diluted with D5W or 0.9% NaCl to prevent vein irritation. Do not administer solution that is discolored or contains particulate matter. Do not refrigerate or freeze; stable for 24 hr at room temperature. Use diluted solution within 24 hr. Concentration: Undiluted: 24 mg/mL; Diluted: 12 mg/mL.
    • Dose is based on patient weight; excess solution may be discarded from bottle before administration to prevent overdosage.
    • Patients who experience progression of CMV retinitis during maintenance therapy may be retreated with induction therapy followed by maintenance therapy.
  • Rate: Administer at a rate not to exceed 1 mg/kg/min.
    • Infuse solution via infusion pump to ensure accurate infusion rate.
  • Y-Site Compatibility:
    • aldesleukin
    • alemtuzumab
    • amikacin
    • aminocaproic acid
    • aminophylline
    • amphotericin B liposomal
    • ampicillin
    • ampicillin/sulbactam
    • anidulafungin
    • argatroban
    • arsenic trioxide
    • atracurium
    • azithromycin
    • aztreonam
    • bivalirudin
    • bleomycin
    • bumetanide
    • buprenorphine
    • busulfan
    • butorphanol
    • carboplatin
    • carmustine
    • cefazolin
    • cefepime
    • cefotaxime
    • cefotetan
    • cefoxitin
    • ceftazidime
    • ceftriaxone
    • cefuroxime
    • chloramphenicol
    • cisatracurium
    • cisplatin
    • clindamycin
    • cyclophosphamide
    • cyclosporine
    • cytarabine
    • dacarbazine
    • dactinomycin
    • daptomycin
    • defibrotide
    • dexamethasone
    • dexmedetomidine
    • dexrazoxane
    • diltiazem
    • docetaxel
    • dopamine
    • doxorubicin liposomal
    • enalaprilat
    • ephedrine
    • epinephrine
    • eptifibatide
    • ertapenem
    • erythromycin
    • esmolol
    • etoposide
    • etoposide phosphate
    • famotidine
    • fentanyl
    • fluconazole
    • flucytosine
    • fludarabine
    • fluorouracil
    • fosphenytoin
    • furosemide
    • gemcitabine
    • gemtuzumab ozogamicin
    • gentamicin
    • glycopyrrolate
    • granisetron
    • heparin
    • hetastarch
    • hydrocortisone
    • hydromorphone
    • ifosfamide
    • imipenem/cilastatin
    • insulin, regular
    • irinotecan
    • isoproterenol
    • ketorolac
    • levofloxacin
    • lidocaine
    • linezolid
    • magnesium sulfate
    • mannitol
    • melphalan
    • meperidine
    • meropenem
    • mesna
    • methadone
    • methotrexate
    • metoclopramide
    • metoprolol
    • metronidazole
    • milrinone
    • mitomycin
    • morphine
    • nafcillin
    • nalbuphine
    • naloxone
    • nitroglycerin
    • nitroprusside
    • octreotide
    • oxacillin
    • oxaliplatin
    • oxytocin
    • paclitaxel
    • palonosetron
    • pamidronate
    • pantoprazole
    • pemetrexed
    • penicillin G potassium
    • pentobarbital
    • phenobarbital
    • phentolamine
    • phenylephrine
    • piperacillin/tazobactam
    • potassium acetate
    • potassium chloride
    • potassium phosphates
    • procainamide
    • propranolol
    • remifentanil
    • rocuronium
    • sodium acetate
    • sodium bicarbonate
    • sodium phosphates
    • succinylcholine
    • sufentanil
    • tacrolimus
    • theophylline
    • thiotepa
    • tigecycline
    • tirofiban
    • tobramycin
    • vecuronium
    • vinblastine
    • vincristine
    • voriconazole
    • zidovudine
    • zoledronic acid
  • Y-Site Incompatibility:
    • acyclovir
    • allopurinol
    • amiodarone
    • amphotericin B deoxycholate
    • calcium chloride
    • calcium gluconate
    • caspofungin
    • chlorpromazine
    • ciprofloxacin
    • dantrolene
    • daunorubicin
    • diazepam
    • digoxin
    • diphenhydramine
    • dobutamine
    • doxorubicin hydrochloride
    • droperidol
    • epirubicin
    • ganciclovir
    • haloperidol
    • hydralazine
    • idarubicin
    • labetalol
    • leucovorin
    • methylprednisolone
    • midazolam
    • minocycline
    • mitoxantrone
    • mycophenolate
    • nicardipine
    • norepinephrine
    • ondansetron
    • pentamidine
    • prochlorperazine
    • promethazine
    • topotecan
    • verapamil
    • vinorelbine

Patient/Family Teaching ⬆ ⬇

  • Explain purpose and side effects of medication to patient. Advise patient to read Patient Information before starting therapy. Inform patient that foscarnet is not a cure for CMV retinitis. Progression of retinitis may continue in immunocompromised patients during and after therapy. Advise patients to have regular ophthalmologic exams.
  • Advise patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care provider before taking other medications.
  • May cause dizziness and seizures. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
  • Advise patient to notify health care provider immediately if perioral tingling or numbness in the extremities or paresthesia occurs during or after infusion. If these signs of electrolyte imbalance occur during administration, infusion should be stopped and lab samples for serum electrolyte concentrations obtained immediately.
  • Rep: Advise women of reproductive potential to notify health care provider if pregnancy is planned or suspected and to avoid breastfeeding.

Evaluation/Desired Outcomes ⬆ ⬇

  • Virustatic action against susceptible viruses, including CMV.

US Brand Names ⬆ ⬇

Foscavir

Canadian Brand Names ⬆ ⬇

Vocarvi

Code ⬆

NDC Code