foscarnet (Rx)

Brand and Other Names:Foscavir, Phosphonoformic acid
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

injectable solution

  • 2.4g/100mL

CMV Retinitis

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

Induction: 60 mg/kg q8hr IV x14-21 days; infuse IV over at least 60 min  

Maintenance: 90-120 mg/kg IV qDay; infuse IV over at least 60-90 min

Herpes Simplex

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

Option 1: 40 mg/kg IV q8hr x14-21 days; infuse IV over at least 60 min  

Option 2: 40-60 mg/kg IV q12hr x14-21 days; infuse IV over at least 60 min

Other Information

Administer by slow IV infusion

Prehydrate with 750-1000 mL NS or D5W before first infusion to decrease risk for nephrotoxicity

See prescribing information for dose adjustments for CrCl <1.4 mL/min/kg

<18 years old: Safety and efficacy not established

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Interactions

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              Serious - Use Alternative (35)

              • alfuzosin

                alfuzosin and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • amiodarone

                amiodarone and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • apomorphine

                apomorphine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • arformoterol

                arformoterol and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • aripiprazole

                aripiprazole and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • arsenic trioxide

                arsenic trioxide and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • artemether

                artemether and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • atomoxetine

                atomoxetine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • bacitracin

                foscarnet and bacitracin both increase nephrotoxicity and/or ototoxicity. Avoid or Use Alternate Drug. Avoid concurrent use of bacitracin with other nephrotoxic drugs

              • ceritinib

                ceritinib and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • clozapine

                clozapine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • degarelix

                degarelix and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • desflurane

                desflurane and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • disopyramide

                disopyramide and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • escitalopram

                escitalopram increases toxicity of foscarnet by QTc interval. Avoid or Use Alternate Drug.

              • fexinidazole

                fexinidazole and foscarnet both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.

              • hydroxychloroquine sulfate

                hydroxychloroquine sulfate and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • ibutilide

                foscarnet and ibutilide both increase QTc interval. Avoid or Use Alternate Drug.

              • indapamide

                foscarnet and indapamide both increase QTc interval. Avoid or Use Alternate Drug.

              • ivosidenib

                ivosidenib and foscarnet both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation.

              • lefamulin

                lefamulin and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • macimorelin

                macimorelin and foscarnet both increase QTc interval. Avoid or Use Alternate Drug. Macimorelin causes an increase of ~11 msec in the corrected QT interval. Avoid coadministration with drugs that prolong QT interval, which could increase risk for developing torsade de pointes-type ventricular tachycardia. Allow sufficient washout time of drugs that are known to prolong the QT interval before administering macimorelin.

              • mefloquine

                mefloquine increases toxicity of foscarnet by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.

              • mobocertinib

                mobocertinib and foscarnet both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, reduce mobocertinib dose and monitor QTc interval more frequently.

              • ondansetron

                foscarnet and ondansetron both increase QTc interval. Avoid or Use Alternate Drug. Avoid with congenital long QT syndrome; ECG monitoring recommended with concomitant medications that prolong QT interval, electrolyte abnormalities, CHF, or bradyarrhythmias.

              • pentamidine

                foscarnet and pentamidine both increase QTc interval. Avoid or Use Alternate Drug.

              • pimozide

                foscarnet and pimozide both increase QTc interval. Avoid or Use Alternate Drug.

              • procainamide

                foscarnet and procainamide both increase QTc interval. Avoid or Use Alternate Drug.

              • quinidine

                quinidine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

              • ribociclib

                ribociclib increases toxicity of foscarnet by QTc interval. Avoid or Use Alternate Drug.

              • sotalol

                foscarnet and sotalol both increase QTc interval. Avoid or Use Alternate Drug.

              • umeclidinium bromide/vilanterol inhaled

                foscarnet increases toxicity of umeclidinium bromide/vilanterol inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.

              • vandetanib

                foscarnet, vandetanib. Either increases toxicity of the other by QTc interval. Avoid or Use Alternate Drug. Avoid coadministration with drugs known to prolong QT interval; if a drug known to prolong QT interval must be used, more frequent ECG monitoring is recommended.

              • vemurafenib

                vemurafenib and foscarnet both increase QTc interval. Avoid or Use Alternate Drug. Concomitant use of vemurafenib with drugs that prolong QT interval is not recommended.

              • vilanterol/fluticasone furoate inhaled

                foscarnet increases toxicity of vilanterol/fluticasone furoate inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.

              Monitor Closely (102)

              • albuterol

                albuterol and foscarnet both increase QTc interval. Use Caution/Monitor.

              • alfuzosin

                foscarnet and alfuzosin both increase QTc interval. Use Caution/Monitor.

              • amikacin

                amikacin and foscarnet both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • amitriptyline

                amitriptyline and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • amoxapine

                amoxapine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • amphotericin B deoxycholate

                amphotericin B deoxycholate and foscarnet both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely.

              • artemether/lumefantrine

                foscarnet and artemether/lumefantrine both increase QTc interval. Modify Therapy/Monitor Closely.

              • bedaquiline

                foscarnet and bedaquiline both increase QTc interval. Modify Therapy/Monitor Closely. ECG should be monitored closely

              • carboplatin

                carboplatin and foscarnet both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • chlorpromazine

                chlorpromazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • cidofovir

                cidofovir and foscarnet both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely.

              • cisplatin

                cisplatin and foscarnet both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • citalopram

                foscarnet and citalopram both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended, along with drugs that may prolong the QT interval.

              • clarithromycin

                clarithromycin and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • clomipramine

                clomipramine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • contrast media (iodinated)

                contrast media (iodinated) and foscarnet both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • crizotinib

                crizotinib and foscarnet both increase QTc interval. Use Caution/Monitor. ECG monitoring is recommended, along with drugs that may prolong the QT interval.

              • cyclosporine

                cyclosporine and foscarnet both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • dasatinib

                dasatinib and foscarnet both increase QTc interval. Use Caution/Monitor.

              • desipramine

                desipramine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • dichlorphenamide

                dichlorphenamide and foscarnet both decrease serum potassium. Use Caution/Monitor.

              • dofetilide

                dofetilide and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • dolasetron

                dolasetron and foscarnet both increase QTc interval. Use Caution/Monitor.

              • doxepin

                doxepin and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • dronedarone

                dronedarone and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • droperidol

                droperidol and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • elvitegravir/cobicistat/emtricitabine/tenofovir DF

                foscarnet and elvitegravir/cobicistat/emtricitabine/tenofovir DF both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • epinephrine

                epinephrine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • epinephrine racemic

                epinephrine racemic and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • erythromycin base

                erythromycin base and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • erythromycin ethylsuccinate

                erythromycin ethylsuccinate and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • erythromycin lactobionate

                erythromycin lactobionate and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • erythromycin stearate

                erythromycin stearate and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • ezogabine

                ezogabine, foscarnet. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Slight and transient QT-prolongation observed with ezogabine, particularly when dose titrated to 1200 mg/day. QT interval should be monitored when ezogabine is prescribed with agents known to increase QT interval.

              • flecainide

                flecainide and foscarnet both increase QTc interval. Use Caution/Monitor.

              • fluconazole

                fluconazole and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • fluoxetine

                fluoxetine and foscarnet both increase QTc interval. Use Caution/Monitor.

              • fluphenazine

                fluphenazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • fluvoxamine

                fluvoxamine and foscarnet both increase QTc interval. Use Caution/Monitor.

              • formoterol

                formoterol and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • fostemsavir

                foscarnet and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.

              • haloperidol

                foscarnet and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.

              • iloperidone

                foscarnet and iloperidone both increase QTc interval. Use Caution/Monitor.

              • imipramine

                imipramine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • indacaterol, inhaled

                indacaterol, inhaled, foscarnet. QTc interval. Use Caution/Monitor. Drugs that are known to prolong the QTc interval may have an increased the risk of ventricular arrhythmias.

              • ioversol

                ioversol and foscarnet both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • ketoconazole

                foscarnet and ketoconazole both increase QTc interval. Modify Therapy/Monitor Closely.

              • lapatinib

                foscarnet and lapatinib both increase QTc interval. Use Caution/Monitor.

              • levofloxacin

                foscarnet and levofloxacin both increase QTc interval. Use Caution/Monitor.

              • lofepramine

                lofepramine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • lumefantrine

                foscarnet and lumefantrine both increase QTc interval. Modify Therapy/Monitor Closely.

              • maprotiline

                maprotiline and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • methadone

                foscarnet and methadone both increase QTc interval. Use Caution/Monitor.

              • mifepristone

                mifepristone, foscarnet. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.

              • moxifloxacin

                foscarnet and moxifloxacin both increase QTc interval. Modify Therapy/Monitor Closely.

              • neomycin PO

                foscarnet and neomycin PO both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely.

              • nilotinib

                foscarnet and nilotinib both increase QTc interval. Modify Therapy/Monitor Closely.

              • nortriptyline

                nortriptyline and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • octreotide

                foscarnet and octreotide both increase QTc interval. Modify Therapy/Monitor Closely.

              • octreotide (Antidote)

                foscarnet and octreotide (Antidote) both increase QTc interval. Modify Therapy/Monitor Closely.

              • ofloxacin

                foscarnet and ofloxacin both increase QTc interval. Use Caution/Monitor.

              • olodaterol inhaled

                foscarnet and olodaterol inhaled both increase QTc interval. Use Caution/Monitor. Drugs that prolong the QTc interval and may potentiate the effects of beta2 agonists on the cardiovascular system; increased risk of ventricular arrhythmias

              • osilodrostat

                osilodrostat and foscarnet both increase QTc interval. Use Caution/Monitor.

              • osimertinib

                osimertinib and foscarnet both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.

              • oxaliplatin

                foscarnet and oxaliplatin both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • ozanimod

                ozanimod and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.

              • paliperidone

                foscarnet and paliperidone both increase QTc interval. Use Caution/Monitor.

              • paroxetine

                foscarnet and paroxetine both increase QTc interval. Use Caution/Monitor.

              • pasireotide

                foscarnet and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.

              • peramivir

                foscarnet increases levels of peramivir by decreasing renal clearance. Use Caution/Monitor. Caution when peramivir coadministered with nephrotoxic drugs.

              • perphenazine

                perphenazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • posaconazole

                foscarnet and posaconazole both increase QTc interval. Use Caution/Monitor.

              • prochlorperazine

                prochlorperazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • promazine

                promazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • promethazine

                promethazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • protriptyline

                protriptyline and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • quetiapine

                quetiapine, foscarnet. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.

              • quinine

                foscarnet and quinine both increase QTc interval. Use Caution/Monitor.

              • ranolazine

                foscarnet and ranolazine both increase QTc interval. Use Caution/Monitor.

              • rilpivirine

                rilpivirine increases toxicity of foscarnet by QTc interval. Use Caution/Monitor. Rilpivirine should be used with caution when co-administered with a drug with a known risk of Torsades de Pointes.

              • risperidone

                foscarnet and risperidone both increase QTc interval. Use Caution/Monitor.

              • romidepsin

                foscarnet and romidepsin both increase QTc interval. Use Caution/Monitor.

              • selpercatinib

                selpercatinib increases toxicity of foscarnet by QTc interval. Use Caution/Monitor.

              • sodium sulfate/?magnesium sulfate/potassium chloride

                sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of foscarnet by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

              • sodium sulfate/potassium sulfate/magnesium sulfate

                sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of foscarnet by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

              • sorafenib

                sorafenib and foscarnet both increase QTc interval. Use Caution/Monitor.

              • streptozocin

                foscarnet and streptozocin both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • sulfamethoxazole

                sulfamethoxazole and foscarnet both increase QTc interval. Use Caution/Monitor.

              • tacrolimus

                foscarnet and tacrolimus both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • teicoplanin

                foscarnet and teicoplanin both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • telavancin

                foscarnet and telavancin both increase QTc interval. Use Caution/Monitor.

              • tenofovir DF

                foscarnet and tenofovir DF both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor.

              • thioridazine

                thioridazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • trazodone

                trazodone and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • trifluoperazine

                trifluoperazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • trimethoprim

                foscarnet and trimethoprim both increase QTc interval. Use Caution/Monitor.

              • trimipramine

                trimipramine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

              • tropisetron

                foscarnet and tropisetron both increase QTc interval. Use Caution/Monitor.

              • venlafaxine

                foscarnet and venlafaxine both increase QTc interval. Use Caution/Monitor.

              • voclosporin

                voclosporin, foscarnet. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.

              • voriconazole

                foscarnet and voriconazole both increase QTc interval. Use Caution/Monitor.

              • ziprasidone

                foscarnet and ziprasidone both increase QTc interval. Modify Therapy/Monitor Closely.

              Minor (30)

              • acyclovir

                acyclovir and foscarnet both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • adefovir

                adefovir and foscarnet both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • alendronate

                foscarnet increases effects of alendronate by pharmacodynamic synergism. Minor/Significance Unknown. Risk of severe hypocalcemia.

              • azithromycin

                azithromycin and foscarnet both increase QTc interval. Minor/Significance Unknown.

              • capreomycin

                capreomycin and foscarnet both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • cephaloridine

                cephaloridine and foscarnet both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • chloroquine

                chloroquine increases toxicity of foscarnet by QTc interval. Minor/Significance Unknown.

              • ciprofloxacin

                ciprofloxacin, foscarnet. Mechanism: unknown. Minor/Significance Unknown. Based on 2 case reports it was reported that there is a potential for an increased risk of seizures.

              • colistin

                colistin and foscarnet both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • entecavir

                foscarnet, entecavir. Either increases levels of the other by decreasing renal clearance. Minor/Significance Unknown. Coadministration with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of either entecavir or the coadministered drug.

              • etidronate

                foscarnet increases effects of etidronate by pharmacodynamic synergism. Minor/Significance Unknown. Risk of severe hypocalcemia.

              • fleroxacin

                fleroxacin, foscarnet. Mechanism: unknown. Minor/Significance Unknown. Risk of tonic clonic seizure.

              • gemifloxacin

                gemifloxacin, foscarnet. Mechanism: unknown. Minor/Significance Unknown. Risk of tonic clonic seizure.

              • gentamicin

                foscarnet and gentamicin both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • ibandronate

                foscarnet increases effects of ibandronate by pharmacodynamic synergism. Minor/Significance Unknown. Risk of severe hypocalcemia.

              • levofloxacin

                levofloxacin, foscarnet. Mechanism: unknown. Minor/Significance Unknown. Risk of tonic clonic seizure.

              • methoxyflurane

                foscarnet and methoxyflurane both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • moxifloxacin

                moxifloxacin, foscarnet. Mechanism: unknown. Minor/Significance Unknown. Risk of tonic clonic seizure.

              • ofloxacin

                ofloxacin, foscarnet. Mechanism: unknown. Minor/Significance Unknown. Risk of tonic clonic seizure.

              • pamidronate

                foscarnet increases effects of pamidronate by pharmacodynamic synergism. Minor/Significance Unknown. Risk of severe hypocalcemia.

              • paromomycin

                foscarnet and paromomycin both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • pazopanib

                foscarnet and pazopanib both increase QTc interval. Minor/Significance Unknown.

              • pentamidine

                foscarnet and pentamidine both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

                foscarnet, pentamidine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of severe hypocalcemia.

              • polymyxin B

                foscarnet and polymyxin B both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • risedronate

                foscarnet increases effects of risedronate by pharmacodynamic synergism. Minor/Significance Unknown. Risk of severe hypocalcemia.

              • streptomycin

                foscarnet and streptomycin both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • tiludronate

                foscarnet increases effects of tiludronate by pharmacodynamic synergism. Minor/Significance Unknown. Risk of severe hypocalcemia.

              • tobramycin

                foscarnet and tobramycin both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • vancomycin

                foscarnet and vancomycin both increase nephrotoxicity and/or ototoxicity. Minor/Significance Unknown.

              • zoledronic acid

                foscarnet increases effects of zoledronic acid by pharmacodynamic synergism. Minor/Significance Unknown. Risk of severe hypocalcemia.

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              Adverse Effects

              >10%

              Fever (65%)

              Nausea (47%)

              Anemia (33%)

              Vomiting (33%)

              Diarrhea (30%)

              Abnormal renal function/decreased CrCl (27%)

              Headache (26%)

              Seizures (10%)

              1-10%

              Fatigue

              Depression

              Confusion

              Anxiety

              Dizziness

              Hypoesthesia

              Malaise

              Rash

              Electrolyte imbalance (especially potassium, calcium, magnesium, and phosphorus)

              Leukopenia

              Neutropenia

              Postmarketing reports

              Esophageal ulceration, renal tubular acidosis, renal tubular necrosis, and crystal-induced nephropathy, status epilepticus, ventricular arrhythmia, prolongation of QT interval, torsade de pointes, gamma GT increased, diabetes insipidus (usually nephrogenic), renal calculus, Fanconi syndrome acquired, hypercalcemia, hypernatremia, and muscle disorders including myopathy, myositis, administration site extravasation, localized edema, hypersensitivity reactions (including anaphylactic shock, urticaria and angioedema) (see WARNINGS section), gastrointestinal hemorrhage, increased lipase, glomerulonephritis, nephrotic syndrome, proteinuria

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              Warnings

              Black Box Warnings

              Renal impairment is the major toxicity; reduce nephrotoxicity risk by IV prehydration with normal saline

              Monitor serum creatinine level, and, if indicated, adjust dose according to renal impairment

              Seizures, related to alterations in plasma minerals and electrolytes, reported; mineral and electrolyte supplementation may be required

              Indicated for use only in immunocompromised patients with cytomegalovirus (CMV) retinitis and mucocutaneous acyclovir-resistant herpes simplex virus (HSV) infections

              Contraindications

              Hypersensitivity

              Cautions

              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

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              Pregnancy & Lactation

              Pregnancy Category: C

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

              Pregnancy Categories

              A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

              B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

              C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

              D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

              X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

              NA: Information not available.

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              Pharmacology

              Mechanism of Action

              Inhibits activity of pyrophosphate binding site on virus-specific DNA polymerases and reverse transcriptases; active against CMV, HSV-1, and HSV-2

              Absorption

              Peak Plasma Concentration: 589 µM (60 mg/kg q8hr), 623 µM (90 mg/kg q12hr)

              Distribution

              Protein Bound: 14-17%

              Volume of distribution: 0.41 L/kg (60 mg/kg q8hr), 0.52 L/kg (90 mg/kg q12hr)

              Elimination

              Half-life: 4 hr (60 mg/kg q8hr); 3.3 hr (90 mg/kg q12hr)

              Dialyzable: Not evaluated

              Renal clearance: 5.6 L/hr (60 mg/kg q8hr), 6.4 L/hr (90 mg/kg q12hr)

              Total body clearance: 6.2 L/hr (60 mg/kg q8hr); 7.1 L/hr (90 mg/kg q12hr)

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              Administration

              IV Incompatibilities

              Y-site: acyclovir, amphotericin B, diazepam, digoxin, diphenhydramine, dobutamine, droperidol, ganciclovir, haloperidol, leucovorin, lorazepam, midazolam, pentamidine, phenytoin, prochlorperazine edisylate, promethazine, TMP-SMX

              IV Compatabilities

              Solution: D5W, NS

              Additive: KCl

              Y-site (partial list): aldesleukin, amikacin, aminophylline, ampicillin, aztreonam, most cephalosporins, clindamycin, fluconazole, furosemide, heparin, metronidazole, morphine, tobramycin, vancomycin (maybe vancomycin concentration dependant)

              IV Preparation

              Should be diluted in D5W or NS & transferred to PVC containers

              For peripheral line administration, dilute to 12 mg/mL with D5W or NS

              For central line administration, may administer undiluted

              IV Administration

              Use an infusion pump, not exceeding 1 mg/kg/min

              Adult induction doses of 60 mg/kg are administered over a minimum 1 hr

              Adult maintenance doses of 90-120 mg are infused over 2 hr

              Storage

              Store at room temp

              Protect from temperatures >40°C and from freezing

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              Images

              BRAND FORM. UNIT PRICE PILL IMAGE
              Foscavir intravenous
              -
              24 mg/mL solution

              Copyright © 2010 First DataBank, Inc.

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              Patient Handout

              Patient Education
              foscarnet intravenous

              FOSCARNET SODIUM - INJECTION

              (foss-KAR-net)

              COMMON BRAND NAME(S): Foscavir

              WARNING: This medication is used only for cytomegalovirus (CMV) eye infections and acyclovir-resistant herpes infections.Foscarnet may cause very serious kidney problems. Tell your doctor right away if you develop signs of kidney problems, such as a change in the amount of urine. Your doctor may need to adjust your dose.This medication has caused seizures in some people due to changes in blood chemistry (minerals and electrolytes). Your doctor may prescribe additional minerals and/or electrolytes to prevent seizures.It is important that you receive appropriate amounts of fluid (hydration) while using this medication.Your doctor will monitor your blood and kidneys while you are using this medication.

              USES: This medication is used to control cytomegalovirus (CMV) eye infections (CMV retinitis) in persons with AIDS. This medication is an antiviral that works by stopping the growth of viruses. Controlling CMV retinitis can help decrease the risk of blindness from the infection. Foscarnet is sometimes combined with another antiviral drug, ganciclovir, when the CMV infection does not respond to either drug used alone for treatment.This medication is also used to treat herpes infections (HSV) that do not respond to treatment with acyclovir (acyclovir-resistant).This medication is not a cure for CMV or HSV diseases.

              HOW TO USE: This medication is given by injection into a vein by a health care professional in a hospital or clinic setting. If you are using this medication at home, learn all preparation and usage instruction from your health care professional. If you have any questions about using this medication properly, consult your doctor or pharmacist.Before using this product, check it visually for particles or discoloration. If either is present, do not use the liquid. It is usually infused slowly over 1 to 2 hours using an infusion pump. Infusing this medication too quickly can result in serious side effects. Do not mix with any other medications. When starting this medication, you will receive 2 to 3 doses per day for the first 2 to 3 weeks of treatment. This starting period is called "induction." Once induction is completed, you will then be given this medication usually once a day for the remainder of treatment. Dosage is based on your weight, kidney function, medical condition, and response to treatment.To prevent kidney damage, it is important to drink plenty of fluids while using this medication. Fluids may be given by vein to make sure you get enough.Antivirals work best when the amount of medicine in your body is kept at a constant level. Use this drug at evenly spaced intervals.It is very important to continue using this medication exactly as prescribed by your doctor. Stopping treatment too soon may result in ineffective treatment.Do not use more of this drug or infuse it more often or faster than prescribed by your doctor. Your condition will not improve faster, and you may experience side effects.If skin contact occurs, flush with plenty of water. If irritation occurs, contact your doctor right away.Learn how to store and discard needles, medical supplies, and any unused medication safely. Consult your pharmacist. Never reuse needles or syringes.

              SIDE EFFECTS: See also Warning section.Because this medication is used in patients who use other medications, it is difficult to tell which side effects are caused by foscarnet. Nausea, vomiting, headache, diarrhea, dizziness, loss of appetite, and increased sweating have been reported. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: mental/mood changes (e.g., depression, anxiety), new vision problems, irregular heartbeat, muscle cramps/spasms, weakness, fast breathing, unusual tiredness, painful urination, irritation/sores on the penis, vaginal irritation/sores, signs of infection (such as fever, persistent sore throat).Get medical help right away if you have any very serious side effects, including: seizures.You may experience redness, irritation, or pain at the injection site. Tell your doctor if this occurs. Also tell your doctor if you experience tingling or numbness of the hands or feet, or tingling around your mouth during or after the infusion. Your doctor may need to adjust your dose.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

              PRECAUTIONS: Before using foscarnet, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease, kidney disease (including being on dialysis), dehydration, low electrolyte levels (calcium, magnesium, potassium, phosphate), nervous system problems (such as a history of seizures), a low sodium diet.This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Caution is advised when using this drug in children because they may be more sensitive to the effects of the drug, especially the effects on developing bones.Older adults may be more sensitive to the side effects of this drug, especially kidney problems.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is not known whether this drug passes into breast milk. Because of the possible harm to the infant, breast-feeding is not recommended.

              DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: drugs that may harm the kidneys (including amphotericin B, cidofovir, aminoglycosides such as amikacin/gentamicin/tobramycin), pentamidine, "water pills" (diuretics), zidovudine.

              OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: seizures, tingling around the mouth, numbness/tingling in arms/legs.

              NOTES: Do not share this medication with others.This medication is usually first given in the hospital where your condition can be monitored closely. Laboratory and/or medical tests (e.g., kidney function, electrolytes levels, complete blood count, regular eye exams) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

              MISSED DOSE: It is important to get this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule. Do not double the dose to catch up.

              STORAGE: Store at room temperature away from light and heat. Keep below 104 degrees F (40 degrees C). Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

              Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

              IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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              Formulary

              FormularyPatient Discounts

              Adding plans allows you to compare formulary status to other drugs in the same class.

              To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

              Adding plans allows you to:

              • View the formulary and any restrictions for each plan.
              • Manage and view all your plans together – even plans in different states.
              • Compare formulary status to other drugs in the same class.
              • Access your plan list on any device – mobile or desktop.

              The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

              Tier Description
              1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
              2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
              3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
              4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              NC NOT COVERED – Drugs that are not covered by the plan.
              Code Definition
              PA Prior Authorization
              Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
              QL Quantity Limits
              Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
              ST Step Therapy
              Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
              OR Other Restrictions
              Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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              Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.