Dosing & Uses
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
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (0)
Serious - Use Alternative (69)
- adagrasib
adagrasib, foscarnet. Either increases effects of the other by QTc interval. Avoid or Use Alternate Drug. Each drug prolongs the QTc interval, which may increased the risk of Torsade de pointes, other serious arryhthmias, and sudden death. If coadministration unavoidable, more frequent monitoring is recommended for such patients.
- 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.
- amisulpride
amisulpride and foscarnet both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.
- anagrelide
anagrelide 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.
- asenapine
asenapine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- asenapine transdermal
asenapine transdermal 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
- buprenorphine
buprenorphine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine buccal
buprenorphine buccal and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine subdermal implant
buprenorphine subdermal implant and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine transdermal
buprenorphine transdermal and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine, long-acting injection
buprenorphine, long-acting injection and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- 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.
- donepezil
donepezil and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- efavirenz
efavirenz and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- eliglustat
eliglustat and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- encorafenib
encorafenib and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- entrectinib
entrectinib and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- eribulin
eribulin 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.
- fingolimod
fingolimod and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- gemifloxacin
gemifloxacin and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- granisetron
granisetron and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- hydroxychloroquine sulfate
hydroxychloroquine sulfate and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- hydroxyzine
hydroxyzine 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.
- isoflurane
isoflurane and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- itraconazole
itraconazole and foscarnet 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.
- lithium
lithium 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.
- mirtazapine
mirtazapine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- 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.
- olanzapine
olanzapine and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- 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.
- oxaliplatin
oxaliplatin and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- 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.
- sertraline
sertraline and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- sevoflurane
sevoflurane and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- siponimod
siponimod and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- solifenacin
solifenacin and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- sotalol
foscarnet and sotalol both increase QTc interval. Avoid or Use Alternate Drug.
- sunitinib
sunitinib and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- tacrolimus
tacrolimus and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- tetrabenazine
tetrabenazine and foscarnet 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.
- vorinostat
vorinostat and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
Monitor Closely (106)
- 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.
- deutetrabenazine
deutetrabenazine and foscarnet both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).
- 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.
- levoketoconazole
foscarnet and levoketoconazole both increase QTc interval. Modify Therapy/Monitor Closely.
- 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.
- ublituximab
ublituximab decreases effects of foscarnet by immunosuppressive effects; risk of infection. Use Caution/Monitor.
- valbenazine
valbenazine and foscarnet 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.
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
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
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.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)
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
Images
| BRAND | FORM. | UNIT PRICE | PILL IMAGE |
|---|---|---|---|
| Foscavir intravenous - | 24 mg/mL solution |  | |
| foscarnet intravenous - | 24 mg/mL solution |  |
Copyright © 2010 First DataBank, Inc.
Patient Handout
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 last or get worse, 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 (such as 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 sore throat that doesn't go away, fever).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 unknown if this drug passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.
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. Lab and/or medical tests (such as kidney function, electrolytes levels, complete blood count, regular eye exams) should be done while you are using this medication. Keep all medical and lab appointments. 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 May 2023. Copyright(c) 2023 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.
Formulary
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