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    Drugs & Diseases

    fostemsavir (Rx)

    Brand and Other Names:Rukobia
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    Dosing & Uses

    AdultPediatric

    Dosage Forms & Strengths

    tablet, extended-release

    • 600mg

    HIV Infection

    Indicated in combination with other antiretroviral (ATV) drugs for treatment of HIV-1 infection in heavily treatment-experienced adults with multidrug-resistant HIV-1 infection failing their current antiretroviral treatment (ART) regimen owing to resistance, intolerance, or safety considerations

    600 mg PO BID

    Dosage Modifications

    Any severity of hepatic or renal impairment, including hemodialysis: No dosage adjustment required

    Safety and efficacy not established

    Next:

    Interactions

    Interaction Checker

    and fostemsavir

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        Serious - Use Alternative

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              Contraindicated (23)

              • amobarbital

                amobarbital will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • apalutamide

                apalutamide will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • bosentan

                bosentan will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • butabarbital

                butabarbital will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • butalbital

                butalbital will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • carbamazepine

                carbamazepine will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • dabrafenib

                dabrafenib will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • efavirenz

                efavirenz will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • enzalutamide

                enzalutamide will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • fosphenytoin

                fosphenytoin will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • ivosidenib

                ivosidenib will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • lorlatinib

                lorlatinib will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • lumacaftor/ivacaftor

                lumacaftor/ivacaftor will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • mitotane

                mitotane will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • nafcillin

                nafcillin will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • pentobarbital

                pentobarbital will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • phenobarbital

                phenobarbital will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • phenytoin

                phenytoin will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • primidone

                primidone will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • rifampin

                rifampin will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • rifapentine

                rifapentine will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • secobarbital

                secobarbital will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              • St John's Wort

                St John's Wort will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

              Serious - Use Alternative (5)

              • cabotegravir

                fostemsavir, cabotegravir. Other (see comment). Avoid or Use Alternate Drug. Comment: Cabotegravir plus rilpivirine is a complete regimen. Coadministration with other antiretroviral medications for treating HIV-1 infection is not recommended.

              • elbasvir/grazoprevir

                fostemsavir will increase the level or effect of elbasvir/grazoprevir by Other (see comment). Avoid or Use Alternate Drug. Fostemsavir inhibits OATP1B1/3 transporter. Higher grazoprevir system exposure may increase risk of ALT elevations. Use an alternative HCV regimen if possible.

              • fexinidazole

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

              • rimegepant

                fostemsavir will increase the level or effect of rimegepant by Other (see comment). Avoid or Use Alternate Drug. Fostemsavir inhibits BCRP transporters.

              • voxilaprevir

                fostemsavir will increase the level or effect of voxilaprevir by Other (see comment). Avoid or Use Alternate Drug. Fostemsavir inhibits OATP1B1/3 and BCRP transporters. Higher voxilaprevir system exposure may increase risk of ALT elevations. Use an alternative HCV regimen if possible.

              Monitor Closely (200)

              • albuterol

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

              • alfuzosin

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

              • alpelisib

                fostemsavir will increase the level or effect of alpelisib by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • ambrisentan

                fostemsavir will increase the level or effect of ambrisentan by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • amiodarone

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

              • amitriptyline

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

              • anagrelide

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

              • apomorphine

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

              • arformoterol

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

              • aripiprazole

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

              • arsenic trioxide

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

              • artemether/lumefantrine

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

              • asenapine

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

              • asenapine transdermal

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

              • atomoxetine

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

              • atorvastatin

                fostemsavir will increase the level or effect of atorvastatin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 and BCRP transporters. If possible, avoid coadministration or modify dose of OATP1B1/3 or BCRP substrates coadministered with fostemsavir. Use lowest possible starting dose for statins and monitor for associated adverse events.

              • azithromycin

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

              • bedaquiline

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

              • berotralstat

                fostemsavir increases levels of berotralstat by Other (see comment). Modify Therapy/Monitor Closely. Comment: Reduced dose of berotralstat (a BCRP substrate) to 110 mg/day when coadministered with BCRP inhibitors.

              • bosentan

                fostemsavir will increase the level or effect of bosentan by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • bosutinib

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

              • capecitabine

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

              • caspofungin

                fostemsavir will increase the level or effect of caspofungin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • ceritinib

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

              • chloroquine

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

              • chlorothiazide

                fostemsavir will increase the level or effect of chlorothiazide by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • chlorpromazine

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

              • cimetidine

                fostemsavir will increase the level or effect of cimetidine by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • ciprofloxacin

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

              • clofazimine

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

              • clozapine

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

              • crizotinib

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

              • dabrafenib

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

              • dasatinib

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

              • daunorubicin

                fostemsavir will increase the level or effect of daunorubicin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • daunorubicin liposomal

                fostemsavir will increase the level or effect of daunorubicin liposomal by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • degarelix

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

              • desflurane

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

              • desipramine

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

              • deutetrabenazine

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

              • digoxin

                fostemsavir will increase the level or effect of digoxin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • dipyridamole

                fostemsavir will increase the level or effect of dipyridamole by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • disopyramide

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

              • dofetilide

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

              • dolasetron

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

              • donepezil

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

              • doxepin

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

              • doxorubicin

                fostemsavir will increase the level or effect of doxorubicin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • doxorubicin liposomal

                fostemsavir will increase the level or effect of doxorubicin liposomal by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • dronedarone

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

              • droperidol

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

              • efavirenz

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

              • elagolix

                fostemsavir will increase the level or effect of elagolix by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • eliglustat

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

              • eluxadoline

                fostemsavir will increase the level or effect of eluxadoline by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • enalapril

                fostemsavir will increase the level or effect of enalapril by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • encorafenib

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

              • entrectinib

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

              • eribulin

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

              • erythromycin base

                fostemsavir will increase the level or effect of erythromycin base by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

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

              • erythromycin ethylsuccinate

                fostemsavir will increase the level or effect of erythromycin ethylsuccinate by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

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

              • erythromycin lactobionate

                fostemsavir will increase the level or effect of erythromycin lactobionate by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

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

              • erythromycin stearate

                fostemsavir will increase the level or effect of erythromycin stearate by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

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

              • escitalopram

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

              • ethinylestradiol

                fostemsavir will increase the level or effect of ethinylestradiol by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir. Do not ethinyl estradiol dose of exceed 30 mcg/day.

              • ezetimibe

                fostemsavir will increase the level or effect of ezetimibe by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • ezogabine

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

              • fexofenadine

                fostemsavir will increase the level or effect of fexofenadine by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • fingolimod

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

              • flecainide

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

              • floxuridine

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

              • fluconazole

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

              • fluoxetine

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

              • fluphenazine

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

              • fluvastatin

                fostemsavir will increase the level or effect of fluvastatin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 and BCRP transporters. If possible, avoid coadministration or modify dose of OATP1B1/3 or BCRP substrates coadministered with fostemsavir. Use lowest possible starting dose for statins and monitor for associated adverse events.

              • formoterol

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

              • foscarnet

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

              • gadobenate

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

              • gemifloxacin

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

              • gemtuzumab

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

              • gilteritinib

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

              • glasdegib

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

              • glecaprevir/pibrentasvir

                fostemsavir will increase the level or effect of glecaprevir/pibrentasvir by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • glyburide

                fostemsavir will increase the level or effect of glyburide by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 and BCRP transporters. If possible, avoid coadministration or modify dose of OATP1B1/3 or BCRP substrates coadministered with fostemsavir.

              • goserelin

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

              • granisetron

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

              • haloperidol

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

              • hydroxychloroquine sulfate

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

              • hydroxyzine

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

              • ibutilide

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

              • iloperidone

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

              • imatinib

                fostemsavir will increase the level or effect of imatinib by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 and BCRP transporters. If possible, avoid coadministration or modify dose of OATP1B1/3 or BCRP substrates coadministered with fostemsavir.

              • indacaterol, inhaled

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

              • inotuzumab

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

              • irinotecan

                fostemsavir will increase the level or effect of irinotecan by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • irinotecan liposomal

                fostemsavir will increase the level or effect of irinotecan liposomal by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • isoflurane

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

              • itraconazole

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

              • ivosidenib

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

              • lapatinib

                fostemsavir will increase the level or effect of lapatinib by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

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

              • ledipasvir/sofosbuvir

                fostemsavir will increase the level or effect of ledipasvir/sofosbuvir by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • lefamulin

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

              • leflunomide

                fostemsavir will increase the level or effect of leflunomide by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • lenvatinib

                fostemsavir will increase the level or effect of lenvatinib by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

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

              • letermovir

                fostemsavir will increase the level or effect of letermovir by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • leuprolide

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

              • levalbuterol

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

              • levofloxacin

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

              • lithium

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

              • lofexidine

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

              • loperamide

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

              • lopinavir

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

              • lovastatin

                fostemsavir will increase the level or effect of lovastatin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • lumefantrine

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

              • macimorelin

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

              • mefloquine

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

              • methotrexate

                fostemsavir will increase the level or effect of methotrexate by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 and BCRP transporters. If possible, avoid coadministration or modify dose of OATP1B1/3 or BCRP substrates coadministered with fostemsavir.

              • midostaurin

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

              • mifepristone

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

              • mirtazapine

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

              • mitoxantrone

                fostemsavir will increase the level or effect of mitoxantrone by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • moxifloxacin

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

              • nilotinib

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

              • nitrofurantoin

                fostemsavir will increase the level or effect of nitrofurantoin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • nortriptyline

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

              • ofloxacin

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

              • olanzapine

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

              • olmesartan

                fostemsavir will increase the level or effect of olmesartan by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • olodaterol inhaled

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

              • ombitasvir/paritaprevir/ritonavir & dasabuvir

                fostemsavir will increase the level or effect of ombitasvir/paritaprevir/ritonavir & dasabuvir by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • ondansetron

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

              • osilodrostat

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

              • osimertinib

                fostemsavir will increase the level or effect of osimertinib by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

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

              • oxaliplatin

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

              • oxytocin

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

              • ozanimod

                fostemsavir will increase the level or effect of ozanimod by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • paliperidone

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

              • panobinostat

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

              • pantoprazole

                fostemsavir will increase the level or effect of pantoprazole by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • pasireotide

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

              • pazopanib

                fostemsavir will increase the level or effect of pazopanib by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

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

              • penicillin G aqueous

                fostemsavir will increase the level or effect of penicillin G aqueous by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • pentamidine

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

              • pimavanserin

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

              • pimozide

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

              • pitavastatin

                fostemsavir will increase the level or effect of pitavastatin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 and BCRP transporters. If possible, avoid coadministration or modify dose of OATP1B1/3 or BCRP substrates coadministered with fostemsavir. Use lowest possible starting dose for statins and monitor for associated adverse events.

              • pitolisant

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

              • pravastatin

                fostemsavir will increase the level or effect of pravastatin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir. Use lowest possible starting dose for statins and monitor for associated adverse events.

              • primaquine

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

              • procainamide

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

              • propafenone

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

              • propofol

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

              • quetiapine

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

              • quinidine

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

              • quinine

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

              • ranolazine

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

              • repaglinide

                fostemsavir will increase the level or effect of repaglinide by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • revefenacin

                fostemsavir will increase the level or effect of revefenacin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • ribociclib

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

              • rilpivirine

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

              • riociguat

                fostemsavir will increase the level or effect of riociguat by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • risperidone

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

              • romidepsin

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

              • rosuvastatin

                fostemsavir will increase the level or effect of rosuvastatin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 and BCRP transporters. If possible, avoid coadministration or modify dose of OATP1B1/3 or BCRP substrates coadministered with fostemsavir. Use lowest possible starting dose for statins and monitor for associated adverse events.

              • salmeterol

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

              • saquinavir

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

              • segesterone/ethinyl estradiol

                fostemsavir will increase the level or effect of segesterone/ethinyl estradiol by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir. Do not ethinyl estradiol dose of exceed 30 mcg/day.

              • selexipag

                fostemsavir will increase the level or effect of selexipag by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • selumetinib

                fostemsavir will increase the level or effect of selumetinib by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • sertraline

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

              • sevoflurane

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

              • simvastatin

                fostemsavir will increase the level or effect of simvastatin by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 and BCRP transporters. If possible, avoid coadministration or modify dose of OATP1B1/3 or BCRP substrates coadministered with fostemsavir. Use lowest possible starting dose for statins and monitor for associated adverse events.

              • siponimod

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

              • sofosbuvir

                fostemsavir will increase the level or effect of sofosbuvir by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • solifenacin

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

              • sorafenib

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

              • sotalol

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

              • sulfasalazine

                fostemsavir will increase the level or effect of sulfasalazine by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • sunitinib

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

              • tacrolimus

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

              • talazoparib

                fostemsavir will increase the level or effect of talazoparib by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • telavancin

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

              • telmisartan

                fostemsavir will increase the level or effect of telmisartan by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • terbutaline

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

              • tetrabenazine

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

              • thioridazine

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

              • topotecan

                fostemsavir will increase the level or effect of topotecan by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • toremifene

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

              • trazodone

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

              • triclabendazole

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

              • triptorelin

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

              • troglitazone

                fostemsavir will increase the level or effect of troglitazone by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • ubrogepant

                fostemsavir will increase the level or effect of ubrogepant by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • valsartan

                fostemsavir will increase the level or effect of valsartan by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

              • vandetanib

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

              • vardenafil

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

              • velpatasvir

                fostemsavir will increase the level or effect of velpatasvir by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

              • vemurafenib

                fostemsavir will increase the level or effect of vemurafenib by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

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

              • voriconazole

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

              • ziprasidone

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

              Minor (0)

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                Adverse Effects

                >10%

                Creatinine >1.8 x ULN or 1.5 x baseline (19%)

                1-10%

                Nausea (10%)

                Direct bilirubin >ULN (7%)

                Hemoglobin <9 g/dL (6%)

                Cholesterol ≥300 mg/dL) (5%)

                Lipase >3x ULN (5%)

                Triglycerides >500 mg/dL (5%)

                ALT >5x ULN (5%)

                AST >5x ULN (4%)

                Hyperglycemia >250 mg/dL (4%)

                LDL cholesterol ≥190 mg/dL

                Neutrophils ≤599 cells/mm3 (4%)

                Diarrhea (4%)

                Headache (4%)

                Bilirubin ≥2.6x ULN (3%)

                Urate >12 mg/dL (3%)

                Abdominal pain (3%)

                Dyspepsia (3%)

                Fatigue (3%)

                Rash (3%)

                Sleep disturbance (3%)

                Immune reconstitution inflammatory syndrome (2%)

                Somnolence (2%)

                Vomiting (2%)

                Creatinine kinase ≥10x ULN (2%)

                <2%

                • Cardiac disorders: ECG QT prolonged (asymptomatic)
                • Musculoskeletal disorders: Myalgia
                • Nervous system disorders: Dizziness, dysgeusia, peripheral neuropathy
                • Skin and subcutaneous tissue disorders: Pruritus
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                Warnings

                Contraindications

                Hypersensitivity to fostemsavir or any of its components

                Coadministered strong CYP3A inducers (eg, enzalutamide, carbamazepine, phenytoin, rifampin, mitotane, St John’s wort), as significant decreases in temsavir (the active moiety of fostemsavir) plasma concentrations may occur, which may result in loss of virologic response

                Cautions

                Immune reconstitution syndrome reported with combination antiretroviral therapy; an inflammatory response to indolent or residual opportunistic infections (eg, Mycobacterium avium infection, cytomegalovirus, Pneumocystis jirovecii pneumonia, or tuberculosis) may occur, which may necessitate further evaluation and treatment; autoimmune disorders (eg, Grave disease, polymyositis, Guillain-Barré) also reported

                Monitor liver enzymes in patients coinfected with hepatitis B or C virus; elevated hepatic transaminases observed in greater proportion of coinfected individuals; maintain/initiate effective hepatitis B therapy when initiating fostemsavir to avoid hepatitis B reactivation

                Drug interaction overview

                • CYP3A4 inducers
                  • Contraindicated
                  • Temsavir (active moiety) is a CYP3A4 substrate
                  • Coadministration with strong CYP3A4 inducers significantly decreases temsavir plasma concentrations, which may lead to loss of virologic response and resistance
                • QT prolongation
                  • Caution with history of prolonged QT, torsade de Pointes, or cardiac disease prone to arrhythmias
                  • Caution if coadministered with other drugs known to prolong QT interval
                  • QTc prolongation reported with higher than recommended doses
                  • Geriatric patients may be more prone to QT prolongation
                • OATP and BCRP substrates
                  • Temsavir inhibits OATP1B1, OATP1B3, and BCRP
                  • Caution; OATP1B1/3 or BCRP substrates (eg, grazoprevir, voxilaprevir, ethinyl estradiol, statins) may need to be avoided or require dosage modification
                  • Temsavir inhibits organic anion transporting polypeptide (OATP)1B1/3, which may increase plasma concentration of substrate
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                Pregnancy & Lactation

                Pregnancy

                Antiretroviral pregnancy registry (APR): Clinicians are encouraged to register patients by calling 1-800-258-4263

                Human data are insufficient regarding use during pregnancy to adequately assess a drug-associated risk of birth defects and miscarriage

                Animal studies

                • Oral administration to pregnant rats and rabbits during organogenesis resulted in no adverse developmental effects at clinically relevant temsavir exposures

                Lactation

                The CDC recommends that HIV-1–infected mothers in the United States not breastfeed their infants to avoid risking postnatal transmission of HIV-1 infection

                Unknown if excreted in breast milk, affects milk production, or effects breastfed infants

                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

                Prodrug of temsavir; first-in-class HIV-1 attachment inhibitor that works by binding directly to the glycoprotein 120 (gp120) subunit on the surface of the virus

                By binding to this location on the virus, fostemsavir blocks HIV from attaching to host immune system CD4+ T cells and other immune cells, thereby preventing HIV from infecting those cells and multiplying

                Absorption

                Bioavailability: 26.9%

                Peak plasma time: 2 hr

                Peak plasma concentration: 1700 ng/mL

                Trough concentration: 478 ng/mL

                AUC: 12,900 ng⋅h/mL

                Distribution

                Protein bound: 88.4% (primarily to albumin)

                Vd: 29.5 L

                Metabolism

                Hydrolysis (esterases): 36.1%

                Oxidation (CYP3A4): 21.2%

                UGT: <1%

                Elimination

                Half-life: 11 hr

                Clearance: 17.9 L/hr

                Excretion: Urine (51%; <2% unchanged); feces (33%; 1.1 unchanged)

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                Administration

                Oral Administration

                May take with or without food

                Swallow tablets whole; do not chew, crush, or split

                Missed dose

                • Advise patients to avoid missing doses as it can result in development of resistance
                • If dose is missed; take as soon as remembered
                • Do not double next dose or take more than prescribed dose owing to risk of QT prolongation

                Storage

                Store at 20-25ºC (68-77ºF); excursions permitted to 15-30ºC (59-86ºF)

                Tablets may have slight vinegarlike odor

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                Images

                No images available for this drug.
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                Patient Handout

                A Patient Handout is not currently available for this monograph.
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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.

                Create Your List of Plans

                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.

                View explanations for tiers and restrictions
                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.
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