fosaprepitant (Rx)

Brand and Other Names:Emend IV
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

injection, powder for reconstitution

  • 150mg/vial

Chemotherapy-Induced Nausea & Vomiting

Indicated in combination with other antiemetic agents for prevention of

  • Acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy (HEC) including high-dose cisplatin
  • Delayed nausea and vomiting associated with initial and repeat courses of moderately emetogenic cancer chemotherapy (MEC)

HEC

  • Day 1: 150 mg IV infused over 20-30 minutes ~30 minutes before chemotherapy plus dexamethasone 12 mg PO and a 5-HT3 antagonist
  • Day 2: Dexamethasone 8 mg PO in AM
  • Days 3 and 4: Dexamethasone 8 mg PO BID (morning and evening)
  • Note: A 50% dosage reduction of dexamethasone on Days 1 and 2 is recommended to account for a drug interaction with aprepitant

MEC

  • Day 1: 150 mg IV infused over 20-30 minutes ~30 minutes before chemotherapy plus dexamethasone 12 mg PO and a 5-HT3 antagonist

Dosage Modifications

Renal impairment

  • Pharmacokinetics in patients with severe renal impairment and those with end stage renal disease (ESRD) requiring hemodialysis were similar to those of healthy subjects with normal renal function
  • No dosage adjustment necessary with any degree of renal impairment or for patients with ESRD undergoing hemodialysis

Hepatic impairment

  • Mild-to-moderate (Child-Pugh A or B): No dosage adjustment necessary
  • Severe (Child-Pugh C): No clinical or pharmacokinetic data are available

Dosing Considerations

Limitation of use

  • Has not been studied for the treatment of established nausea and vomiting

Dosage Forms & Strengths

injection, powder for reconstitution

  • 150mg/vial

Chemotherapy-Induced Nausea & Vomiting

Indicated adults and children aged 6 months and older for prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy (HEC) including high-dose cisplatin, and for moderately emetogenic cancer chemotherapy (MEC)

IV (single-day chemotherapy regimens)

  • <6 months or weight <6 kg: Safety and efficacy not established
  • 6 months to <2 years: 5 mg/kg IV over 60 minutes ~30 minutes before chemotherapy; not to exceed 150 mg/dose
  • 2 to <12 years: 4 mg/kg IV over 60 minutes ~30 minutes before chemotherapy; not to exceed 150 mg/dose
  • 12-17 years: 150 mg IV over 30 minutes ~30 minutes before chemotherapy
  • In combination with dexamethasone and 5-HT3 antagonist (eg, ondansetron)
    • Recommended dosing for 6 months to 17 years for prevention of nausea and vomiting associated with single-day regimens of HEC or MEC
    • Dexamethasone: If a corticosteroid (eg, dexamethasone) is coadministered, administer 50% of recommended corticosteroid dose on Days 1 and 2; administer 30 minutes prior to chemotherapy treatment on Day 1
    • 5-HT3 antagonist: See selected 5-HT3 antagonist prescribing information for recommended dosage

IV (multiday chemotherapy regimens)

  • NOTE: May administer IV infusion on Days 1, 2, and 3 OR on Days 2 and 3 may use capsules or oral suspension instead
  • <6 months or weight <6 kg: Safety and efficacy not established
  • 6 months to <12 years
    • Day 1: 3 mg/kg IV over 60 minutes ~30 minutes before chemotherapy; not to exceed 115 mg/dose
    • Days 2 and 3 (IV): 2 mg/kg IV over 60 minutes ~30 minutes before chemotherapy; not to exceed 80 mg/dose, OR
    • Days 2 and 3 (oral suspension): 2 mg/kg PO ~30 minutes before chemotherapy; not to exceed 80 mg/dose
  • 12-17 years
    • Day 1: 115 mg IV over 30 minutes ~30 minutes before chemotherapy
    • Days 2 and 3 (IV): 80 mg IV over 30 minutes ~30 minutes before chemotherapy; not to exceed 80 mg/dose, OR
    • Days 2 and 3 (capsules): 80 mg PO ~30 minutes before chemotherapy
    • Dexamethasone: If a corticosteroid (eg, dexamethasone) is coadministered, administer 50% of recommended corticosteroid dose on Days 1 and 2; administer 30 minutes prior to chemotherapy treatment on Day 1
    • 5-HT3 antagonist: See selected 5-HT3 antagonist prescribing information for recommended dosage
Dosage Modifications

Renal impairment

  • Pharmacokinetics in patients with severe renal impairment and those with end stage renal disease (ESRD) requiring hemodialysis were similar to those of healthy subjects with normal renal function
  • No dosage adjustment necessary with any degree of renal impairment or for patients with ESRD undergoing hemodialysis

Hepatic impairment

  • Mild-to-moderate (Child-Pugh A or B): No dosage adjustment necessary
  • Severe (Child-Pugh C): No clinical or pharmacokinetic data are available

Dosing Considerations

Chronic continuous administration is not recommended because it has not been studied, and because the drug interaction profile may change during chronic continuous use

Limitation of use

  • Has not been studied for treatment of established nausea and vomiting
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Interactions

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            Contraindicated (8)

            • chloramphenicol

              chloramphenicol will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • darunavir

              darunavir will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • flibanserin

              fosaprepitant will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of flibanserin with moderate or strong CYP3A4 inhibitors is contraindicated. Severe hypotension or syncope can occur.

            • lomitapide

              fosaprepitant increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.

            • lonafarnib

              fosaprepitant will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lonafarnib is a sensitive CYP3A4 substrate. Coadministration with strong or moderate CYP3A4 inhibitors is contraindicated.

            • pimozide

              fosaprepitant increases levels of pimozide by decreasing metabolism. Contraindicated. Risk of QT interval prolongation.

            • ribociclib

              ribociclib will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • tipranavir

              tipranavir will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            Serious - Use Alternative (72)

            • abametapir

              abametapir will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

            • apalutamide

              apalutamide will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.

            • avapritinib

              fosaprepitant will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of avapritinib with moderate CYP3A4 inhibitors. If unable to avoid, reduce avapritinib starting dose. See drug monograph Dosage Modifications.

            • axitinib

              fosaprepitant increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with moderate CYP3A4 inhibitors, monitor closely and reduce dose if necessary .

            • bosutinib

              fosaprepitant increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • carbamazepine

              carbamazepine will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • ceritinib

              ceritinib will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • cimetidine

              cimetidine will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • clarithromycin

              clarithromycin will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • cobicistat

              cobicistat will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • cobimetinib

              fosaprepitant will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concurrent short term (14 days or less) use of moderate CYP3A inhibitors is unavoidable for patients who are taking cobimetinib 60 mg, reduce the cobimetinib dose to 20 mg. After discontinuation of a moderate CYP3A inhibitor, resume cobimetinib 60 mg. Use an alternative to a moderate CYP3A inhibitor in patients who are taking a reduced dose of cobimetinib (40 or 20 mg daily).

            • colchicine

              fosaprepitant will increase the level or effect of colchicine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid use of colchicine with strong CYP3A4 inhibitors. If coadministration is necessary, decrease colchicine dose or frequency as recommended in prescribing information. Use of any colchicine product in conjunction with strong CYP3A4 inhibitors is contraindicated in patients with renal or hepatic impairment.

            • conivaptan

              conivaptan will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • dihydroergotamine

              fosaprepitant will increase the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • dihydroergotamine intranasal

              fosaprepitant will increase the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • diltiazem

              diltiazem will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Moderate CYP3A4 inhibitors may increase serum concentrations and/or toxicities of aprepitant.

            • dronedarone

              fosaprepitant will increase the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • elacestrant

              fosaprepitant will increase the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • eliglustat

              fosaprepitant increases levels of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Moderate CYP3A4 inhibitors are not recommended with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers .

            • encorafenib

              fosaprepitant will increase the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use of a moderate CYP3A4 inhibitor is unavoidable, reduce encorafenib dose to one-half of the dose (eg, reduce from 450 mg/day to 225 mg/day). After discontinuing the inhibitor for 3-5 elimination half-lives, resume previous encorafenib dose.

            • entrectinib

              fosaprepitant will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of moderate CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce dose to 200 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing moderate CYP3A inhibitor for 3-5 elimination half-lives.

            • enzalutamide

              enzalutamide will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • ergotamine

              fosaprepitant will increase the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • erythromycin base

              fosaprepitant will increase the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

              erythromycin base will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • erythromycin ethylsuccinate

              fosaprepitant will increase the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

              erythromycin ethylsuccinate will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • erythromycin lactobionate

              fosaprepitant will increase the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

              erythromycin lactobionate will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • erythromycin stearate

              fosaprepitant will increase the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

              erythromycin stearate will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • everolimus

              fosaprepitant will increase the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • fedratinib

              fosaprepitant will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.

            • fentanyl

              fosaprepitant will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

            • fentanyl intranasal

              fosaprepitant will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

            • fentanyl transdermal

              fosaprepitant will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

            • fentanyl transmucosal

              fosaprepitant will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

            • ibrutinib

              fosaprepitant increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for =7 days), interrupt ibrutinib therapy until strong CYP3A4 inhibitor is discontinued.

            • idelalisib

              idelalisib will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

            • infigratinib

              fosaprepitant will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • itraconazole

              itraconazole will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • ivabradine

              fosaprepitant will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ivabradine with moderate CYP3A4 inhibitors.

            • ivosidenib

              ivosidenib will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

            • ketoconazole

              ketoconazole will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • lemborexant

              fosaprepitant will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lemborexant with moderate or strong CYP3A inhibitors.

            • levoketoconazole

              levoketoconazole will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • lovastatin

              fosaprepitant will increase the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • lurbinectedin

              fosaprepitant will increase the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • midazolam intranasal

              fosaprepitant will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of moderate CYP3A4 inhibitors with midazolam intranasal causes higher midazolam systemic exposure, which may prolong sedation.

            • mifepristone

              mifepristone will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • mobocertinib

              fosaprepitant will increase the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use of moderate CYP3A4 inhibitor unavoidable, reduce mobocertinib dose by ~50% (eg, 160 to 80 mg); closely monitor QTc interval.

            • naloxegol

              fosaprepitant will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministation of naloxegol with moderate CYP3A4 inhibitors is unavoidable, reduce naloxegol dose to 12.5 mg qDay

            • nefazodone

              nefazodone will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • neratinib

              fosaprepitant will increase the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inhibitors.

            • olaparib

              fosaprepitant will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with moderate CYP3A inhibitors cannot be avoided, reduce olaparib dose to 200 mg (capsule) or 150 mg (tablet) PO BID. Do not substitute tablets with capsules.

            • pacritinib

              fosaprepitant will decrease the level or effect of pacritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • pazopanib

              fosaprepitant will increase the level or effect of pazopanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of pazopanib with strong CYP3A4 inhibitors if possible; if must coadminister, decrease pazopanib dose to 400 mg/day

            • pemigatinib

              fosaprepitant will increase the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pemigatinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pemigatinib dose.

            • pexidartinib

              fosaprepitant will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.

            • pimozide

              fosaprepitant will increase the level or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Risk of QT interval prolongation.

            • ranolazine

              fosaprepitant will increase the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • rifabutin

              rifabutin will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • rifampin

              rifampin will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • ritonavir

              ritonavir will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • saquinavir

              saquinavir will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • selumetinib

              fosaprepitant will increase the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors cannot be avoided, reduce selumetinib dosage (refer to selumetinib monograph for further information). After discontinuation of the strong or moderate CYP3A4 inhibitor for 3 elimination half-lives, resume selumetinib dose that was taken before initiating the inhibitor.

            • silodosin

              fosaprepitant will increase the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • simvastatin

              fosaprepitant will increase the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • siponimod

              fosaprepitant will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a moderate or strong CYP3A4 inhibitor PLUS a moderate or strong CYP2C9 inhibitor is not recommended.

            • sirolimus

              fosaprepitant will increase the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • St John's Wort

              St John's Wort will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • tazemetostat

              fosaprepitant will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of tazemetostat with moderate CYP3A4 inhibitors. If coadministration is unavoidable, reduce tazemetostat current dose (see drug monograph Dosage Modifications).

            • tolvaptan

              fosaprepitant will increase the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • venetoclax

              fosaprepitant will increase the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If a moderate CYP3A inhibitor must be used, reduce the venetoclax dose by at least 50%. Monitor more closely for signs of venetoclax toxicities.

            • vilazodone

              fosaprepitant increases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If intolerable adverse effects occur when coadministered with moderate CYP3A4 inhibitors, reduce daily dose to 20 mg.

            • voxelotor

              voxelotor will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.

            Monitor Closely (186)

            • acalabrutinib

              fosaprepitant will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease acalabrutinib dose to 100 mg once daily if coadministered with a moderate CYP3A inhibitor.

            • almotriptan

              fosaprepitant will increase the level or effect of almotriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • alprazolam

              fosaprepitant will increase the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • amiodarone

              fosaprepitant will increase the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • amitriptyline

              fosaprepitant will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • aripiprazole

              fosaprepitant will increase the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • armodafinil

              armodafinil will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • artemether/lumefantrine

              fosaprepitant will increase the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • atazanavir

              atazanavir will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • atogepant

              fosaprepitant will decrease the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • atorvastatin

              fosaprepitant will increase the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • avanafil

              fosaprepitant will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; increased levels may result in increased associated adverse events; the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours for patients taking concomitant moderate CYP3A4 inhibitors

            • bazedoxifene/conjugated estrogens

              fosaprepitant will increase the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • belzutifan

              belzutifan will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If unable to avoid coadministration of belzutifan with sensitive CYP3A4 substrates, consider increasing the sensitive CYP3A4 substrate dose in accordance with its prescribing information.

            • bexarotene

              fosaprepitant will increase the level or effect of bexarotene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Altered bexarotene serum concentrations may occur, leading to either an increased risk of bexarotene-related adverse reactions or a risk of decreased bexarotene efficacy.

            • bortezomib

              fosaprepitant will increase the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • bosentan

              bosentan will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • brexpiprazole

              fosaprepitant will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP3A4 inhibitor PLUS a strong/moderate CYP2D6 inhibitor.

            • budesonide

              fosaprepitant will increase the level or effect of budesonide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              budesonide will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • buprenorphine subdermal implant

              fosaprepitant will increase the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inhibitors for signs and symptoms of overmedication. If the dose of the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inhibitor is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for withdrawal.

            • buprenorphine, long-acting injection

              fosaprepitant will increase the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inhibitors should be monitored to ensure buprenorphine plasma levels are adequate. Within 2 weeks, if signs and symptoms of buprenorphine toxicity or overdose occur and the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.

            • buspirone

              fosaprepitant will increase the level or effect of buspirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • butabarbital

              butabarbital will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • butalbital

              butalbital will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • cabazitaxel

              fosaprepitant will increase the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A4 inhibitors.

            • cabozantinib

              fosaprepitant will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • cannabidiol

              fosaprepitant will increase the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a moderate CYP3A4 inhibitor.

            • carbamazepine

              fosaprepitant will increase the level or effect of carbamazepine by decreasing metabolism. Modify Therapy/Monitor Closely. Monitor plasma levels when used concomitantly

            • cenobamate

              cenobamate will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.

            • cilostazol

              fosaprepitant will increase the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • cinacalcet

              fosaprepitant will increase the level or effect of cinacalcet by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • clomipramine

              fosaprepitant will increase the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • clopidogrel

              fosaprepitant will decrease the level or effect of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Inhibition of CYP3A4 will reduce clopidogrel bioactivation

            • clozapine

              fosaprepitant will increase the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • conivaptan

              fosaprepitant will increase the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • conjugated estrogens

              fosaprepitant will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • conjugated estrogens, vaginal

              fosaprepitant will increase the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • cortisone

              fosaprepitant will increase the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              cortisone will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • crizotinib

              fosaprepitant increases levels of crizotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A inhibitors. .

              crizotinib increases levels of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A inhibitors. .

            • crofelemer

              crofelemer increases levels of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.

            • cyclosporine

              fosaprepitant will increase the level or effect of cyclosporine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              cyclosporine will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • dabrafenib

              dabrafenib will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

            • daridorexant

              fosaprepitant will increase the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Daridorexant dose should not exceed 25 mg per night when coadministered with moderate CYP3A4 inhibitors.

            • darifenacin

              fosaprepitant will increase the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              darifenacin will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • darunavir

              fosaprepitant will increase the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • dasatinib

              fosaprepitant will increase the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • deferasirox

              deferasirox will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • deflazacort

              fosaprepitant will increase the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease deflazacort dose to one-third of the recommended dose if coadministered with moderate or strong CYP3A4 inhibitors.

            • desipramine

              fosaprepitant will increase the level or effect of desipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • dexamethasone

              fosaprepitant will increase the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              dexamethasone will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • DHEA, herbal

              DHEA, herbal will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • diazepam

              fosaprepitant will increase the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • dichlorphenamide

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

            • dienogest/estradiol valerate

              fosaprepitant will increase the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for potential adverse effects such as nausea, irregular uterine bleeding, breast tenderness and headache.

            • diltiazem

              fosaprepitant will increase the level or effect of diltiazem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • doxorubicin

              fosaprepitant will increase the level or effect of doxorubicin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • doxorubicin liposomal

              fosaprepitant will increase the level or effect of doxorubicin liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • dronedarone

              dronedarone will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • duvelisib

              duvelisib will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. will increase the level or effect of

            • efavirenz

              efavirenz will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • elagolix

              elagolix will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.

            • eletriptan

              fosaprepitant will increase the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • elvitegravir/cobicistat/emtricitabine/tenofovir DF

              elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

            • encorafenib

              encorafenib, fosaprepitant. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.

            • erlotinib

              fosaprepitant will increase the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • eslicarbazepine acetate

              eslicarbazepine acetate will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • estradiol

              fosaprepitant will increase the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • estrogens conjugated synthetic

              fosaprepitant will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • estrogens esterified

              fosaprepitant will increase the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Estrogens are CYP3A4 substrates, and the efficacy of estrogens when used for hormone replacement may be reduced.

            • estropipate

              fosaprepitant will increase the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • etonogestrel

              fosaprepitant will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • etoposide

              fosaprepitant will increase the level or effect of etoposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • etravirine

              fosaprepitant will increase the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              etravirine will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • fedratinib

              fedratinib will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.

            • felodipine

              fosaprepitant will increase the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • fesoterodine

              fosaprepitant will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • finerenone

              fosaprepitant will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.

            • fluconazole

              fluconazole will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • fludrocortisone

              fosaprepitant will increase the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              fludrocortisone will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • fosamprenavir

              fosaprepitant will increase the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • fosphenytoin

              fosphenytoin will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • grapefruit

              grapefruit will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • griseofulvin

              griseofulvin will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • guanfacine

              fosaprepitant will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.

            • hydrocortisone

              fosaprepitant will increase the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              hydrocortisone will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • hydroxyprogesterone caproate

              fosaprepitant will increase the level or effect of hydroxyprogesterone caproate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • ifosfamide

              fosaprepitant decreases effects of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for ifosfamide neurotoxicity (eg, visual and auditory hallucinations, somnolence, confusion, delirium) if combined with fosaprepitant. Consider also monitoring for decreased ifosfamide efficacy.

            • iloperidone

              fosaprepitant will increase the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              iloperidone increases levels of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.

            • imipramine

              fosaprepitant will increase the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • indinavir

              fosaprepitant will increase the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              indinavir will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • irinotecan

              fosaprepitant will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • irinotecan liposomal

              fosaprepitant will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • isavuconazonium sulfate

              fosaprepitant will decrease the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • isoniazid

              isoniazid will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • istradefylline

              istradefylline will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.

            • ivosidenib

              fosaprepitant will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with moderate CYP3A4 inhibitors may increase ivosidenib plasma concentrations, thus increasing the risk of QTc prolongation. Monitor for increased risk of QTc interval prolongation.

            • ixabepilone

              fosaprepitant will increase the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • lapatinib

              fosaprepitant will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • larotrectinib

              larotrectinib will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • lefamulin

              fosaprepitant will increase the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for adverse effects if lefamulin is coadministered with moderate CYP3A inhibitors.

            • lenacapavir

              lenacapavir will increase the level or effect of fosaprepitant by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor. Lencapavir (a moderate CYP3A4 inhibitor) may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates. Reduce acalabrutinib dose from 100 mg PO Q12hr to 100 mg PO qDay when coadministered with lenacapavir.

              lenacapavir will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir (a moderate CYP3A4 inhibitor) may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.

            • letermovir

              letermovir increases levels of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • levamlodipine

              fosaprepitant will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate and strong CYP3A inhibitors results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is coadministered with CYP3A inhibitors to determine the need for dose adjustment.

            • levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

              fosaprepitant will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.

            • linagliptin

              fosaprepitant will increase the level or effect of linagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of alternative treatments is strongly recommended when linagliptin is to be administered with a CYP3A4 inducer

            • lopinavir

              fosaprepitant will increase the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              lopinavir will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • loratadine

              fosaprepitant will increase the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • lorlatinib

              lorlatinib will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • lumateperone

              fosaprepitant will increase the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce lumateperone dose to 21 mg/day if coadministered with moderate CYP3A4 inhibitors.

            • lumefantrine

              fosaprepitant will increase the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • lurasidone

              fosaprepitant increases levels of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Manufacturer recommends decreasing starting dose of lurasidone to 20 mg/day and maximum daily dose of lurasidone 80 mg when coadministered with moderate CYP3A4 inhibitors. Concurrent use may increase risk of lurasidone-related adverse reactions.

            • maraviroc

              fosaprepitant will increase the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • marijuana

              marijuana will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • mavacamten

              fosaprepitant will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

              fosaprepitant will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

            • mefloquine

              fosaprepitant will increase the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • mestranol

              fosaprepitant will increase the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • methadone

              fosaprepitant will increase the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • methylprednisolone

              fosaprepitant will increase the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              methylprednisolone will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • metronidazole

              metronidazole will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • miconazole vaginal

              miconazole vaginal will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • midazolam

              fosaprepitant will increase the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • mifepristone

              fosaprepitant will increase the level or effect of mifepristone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • mitotane

              mitotane decreases levels of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.

            • naldemedine

              fosaprepitant increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.

            • nelfinavir

              fosaprepitant will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              nelfinavir will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • nevirapine

              nevirapine will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • nicardipine

              fosaprepitant will increase the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • nifedipine

              nifedipine will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • nilotinib

              fosaprepitant will increase the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • nisoldipine

              fosaprepitant will increase the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • oliceridine

              fosaprepitant will decrease the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.

            • oxcarbazepine

              oxcarbazepine will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • palbociclib

              fosaprepitant will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • pentobarbital

              pentobarbital will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • phenobarbital

              phenobarbital will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • phenytoin

              phenytoin will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • posaconazole

              posaconazole will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • prednisolone

              fosaprepitant will increase the level or effect of prednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              prednisolone will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • prednisone

              fosaprepitant will increase the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • primidone

              primidone will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • quetiapine

              fosaprepitant will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • quinidine

              fosaprepitant will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • quinupristin/dalfopristin

              quinupristin/dalfopristin will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • repaglinide

              fosaprepitant will increase the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • rifapentine

              rifapentine will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • rimegepant

              fosaprepitant will increase the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid repeating rimegepant dose within 48 hr if coadministered with a moderate CYP3A4 inhibitor.

            • ritonavir

              fosaprepitant will increase the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • romidepsin

              fosaprepitant will increase the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • rucaparib

              rucaparib will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.

            • rufinamide

              rufinamide will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • ruxolitinib

              fosaprepitant will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • ruxolitinib topical

              fosaprepitant will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • saquinavir

              fosaprepitant will increase the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • secobarbital

              secobarbital will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • sildenafil

              fosaprepitant will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • solifenacin

              fosaprepitant will increase the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • sonidegib

              fosaprepitant will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of sonidegib with moderate CYP3A4 inhibitors. If a moderate CYP3A inhibitor must be used, administer the moderate CYP3A inhibitor for <14 days and monitor closely for adverse reactions, particularly musculoskeletal adverse reactions.

            • stiripentol

              stiripentol, fosaprepitant. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.

            • sufentanil SL

              fosaprepitant will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.

            • sunitinib

              fosaprepitant will increase the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • suvorexant

              fosaprepitant will increase the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease suvorexant starting dose to 5 mg HS if coadministered with moderate CYP3A4 inhibitors

            • tacrolimus

              fosaprepitant will increase the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tadalafil

              fosaprepitant will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tamsulosin

              fosaprepitant increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.

            • tazemetostat

              tazemetostat will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tecovirimat

              tecovirimat will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

            • temsirolimus

              fosaprepitant will increase the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tezacaftor

              fosaprepitant will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tezacaftor dosage regimen if coadministered with a moderate CYP3A inhibitor.

            • theophylline

              fosaprepitant will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tinidazole

              fosaprepitant will decrease the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tipranavir

              fosaprepitant will increase the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tofacitinib

              fosaprepitant increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No specific dose adjustment recommended when tofacitinib coadministered with moderate CYP3A4 inhibitors; decrease tofacitinib dose if coadministered with both moderate CYP3A4 and potent CYP2C19 inhibitors.

            • tolterodine

              fosaprepitant will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • topiramate

              topiramate will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • trabectedin

              fosaprepitant will increase the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • trazodone

              fosaprepitant will increase the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • triamcinolone acetonide injectable suspension

              fosaprepitant will increase the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • triazolam

              fosaprepitant will increase the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • ubrogepant

              fosaprepitant will decrease the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Dose adjustment is recommended with concomitant use of ubrogepant and moderate and weak CYP3A4 inducers. (see Dosage Modifications)

            • vardenafil

              fosaprepitant will increase the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • verapamil

              fosaprepitant will increase the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • voclosporin

              fosaprepitant will increase the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce voclosporin daily dosage to 15.8 mg PO in AM and 7.9 mg PO in PM.

            • voriconazole

              voriconazole will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • warfarin

              fosaprepitant will decrease the level or effect of warfarin by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely. In patients on chronic warfarin therapy, monitor INR in the 2-week period, particularly at 7-10 days, following aprepitant or fosaprepitant administration with each chemotherapy cycle

            • zafirlukast

              zafirlukast will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • zanubrutinib

              fosaprepitant will increase the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce zanubrutinib dose when coadministered with a moderate CYP3A4 inhibitor. Interrupt dose as recommended for adverse reactions. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib. See zanubrutinib Dosage Modifications for precise recommendation.

            Minor (54)

            • acetazolamide

              acetazolamide will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • alfentanil

              fosaprepitant will increase the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • alfuzosin

              fosaprepitant will increase the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • alosetron

              fosaprepitant will increase the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • amlodipine

              fosaprepitant will increase the level or effect of amlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • amobarbital

              amobarbital will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • anastrozole

              anastrozole will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • armodafinil

              fosaprepitant will increase the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • atazanavir

              fosaprepitant will increase the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • bosentan

              fosaprepitant will increase the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • cevimeline

              fosaprepitant will increase the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • clarithromycin

              fosaprepitant will increase the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • cyclophosphamide

              cyclophosphamide will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • dapsone

              fosaprepitant will increase the level or effect of dapsone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • disopyramide

              fosaprepitant will increase the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • docetaxel

              fosaprepitant will increase the level or effect of docetaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • donepezil

              fosaprepitant will increase the level or effect of donepezil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • dutasteride

              fosaprepitant will increase the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • efavirenz

              fosaprepitant will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • eplerenone

              fosaprepitant will increase the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • estradiol vaginal

              fosaprepitant will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • eucalyptus

              fosaprepitant will increase the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • finasteride

              fosaprepitant will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • galantamine

              fosaprepitant will increase the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • imatinib

              fosaprepitant will increase the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • isradipine

              fosaprepitant will increase the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • itraconazole

              fosaprepitant will increase the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • ketoconazole

              fosaprepitant will increase the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • levoketoconazole

              fosaprepitant will increase the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • mestranol

              fosaprepitant decreases levels of mestranol by increasing metabolism. Minor/Significance Unknown.

            • montelukast

              fosaprepitant will increase the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • nifedipine

              fosaprepitant will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • nimodipine

              fosaprepitant will increase the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • nitrendipine

              fosaprepitant will increase the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • oxybutynin

              fosaprepitant will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • paclitaxel

              fosaprepitant will increase the level or effect of paclitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • paclitaxel protein bound

              fosaprepitant will increase the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • parecoxib

              fosaprepitant will increase the level or effect of parecoxib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • paroxetine

              fosaprepitant, paroxetine. Either decreases levels of the other by unspecified interaction mechanism. Minor/Significance Unknown.

            • pioglitazone

              fosaprepitant will increase the level or effect of pioglitazone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • propafenone

              fosaprepitant will increase the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • quinine

              fosaprepitant will increase the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • ramelteon

              fosaprepitant will increase the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • saxagliptin

              fosaprepitant will increase the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • sufentanil

              fosaprepitant will increase the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • tamoxifen

              fosaprepitant, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).

            • vinblastine

              fosaprepitant will increase the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • vincristine

              fosaprepitant will increase the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • vincristine liposomal

              fosaprepitant will increase the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • vinorelbine

              fosaprepitant will increase the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • zaleplon

              fosaprepitant will increase the level or effect of zaleplon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • ziprasidone

              fosaprepitant will increase the level or effect of ziprasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • zolpidem

              fosaprepitant will increase the level or effect of zolpidem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • zonisamide

              fosaprepitant will increase the level or effect of zonisamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

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            Adverse Effects

            Comparative Data

            In an active-controlled clinical trial in patients receiving MEC, incidence of adverse effects of aprepitant (plus ondansetron and dexamethasone) were similar to ondansetron and dexamethasone alone

            Chemotherapy likely contributes to most of the following adverse effects

            >10%

            Fatigue (15%)

            Diarrhea (13%)

            Neutropenia (8%)

            Asthenia (4%)

            1-10%

            Neutropenia (8%)

            Asthenia (4%)

            Anemia (3%)

            Peripheral neuropathy (3%)

            Infusion-site reactions (2.2%); standard therapy (0.6%)

            Leukopenia (2%)

            Dyspepsia (2%)

            UTI (2%)

            Pain in extremity (2%)

            Postmarketing Reports

            Skin and subcutaneous tissue disorders: Pruritus, rash, urticaria, Stevens-Johnson syndrome/toxic epidermal necrolysis

            Immune system disorders: Hypersensitivity reactions including anaphylaxis and anaphylactic shock

            Nervous system disorders: Ifosfamide-induced neurotoxicity reported after aprepitant and ifosfamide coadministration

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            Warnings

            Contraindications

            Hypersensitivity

            Concomitant pimozide

            Cautions

            Hypersensitivity reactions

            • Serious hypersensitivity reactions, including anaphylaxis and anaphylactic shock, during or soon after administration reported
            • Symptoms may include dyspnea, eye swelling, flushing, pruritus and wheezing
            • Monitor during and after IV administration
            • If hypersensitivity reactions occur, discontinue drug and administer appropriate medical therapy; do not reinitiate treatment in patients who experience these symptoms with previous use

            Infusion site reactions

            • Infusion site reactions (ISRs) reported after IV infusion
            • Majority of severe ISRs, including thrombophlebitis and vasculitis, were reported with concomitant vesicant (anthracycline-based) chemotherapy administration, particularly when associated with extravasation
            • Necrosis was also reported with concomitant vesicant chemotherapy
            • If a severe ISR develops during infusion, discontinue and administer appropriate medical treatment

            Drug interaction overview

            • Fosaprepitant, a prodrug of aprepitant, is a week CYP3A4 inhibitor
            • Aprepitant is a CYP3A4 substrate, inhibitor (weak-to-moderate [dose dependent]), and inducer
            • Aprepitant is also an inducer of CYP2C9
            • Pimozide
              • Contraindicated
              • Coadministration of pimozide (major CYP3A4 substrate) with aprepitant significantly increased plasma concentrations of pimozide, which may prolong QT interval
            • CYP3A4 substrates
              • Concomitant use of aprepitant and CYP3A4 substrates may result in increased plasma concentration of the CYP3A4 drugs
            • Moderate-to-strong CYP3A4 inhibitors
              • Avoid
              • Coadministration of aprepitant or fosaprepitant may increase plasma concentrations and effects of aprepitant
            • Strong CYP3A4 inducers
              • Avoid
              • Coadministration of aprepitant with strong CYP3A4 inducers (eg, rifampin, carbamazepine, phenytoin) may result in a substantial reduction in aprepitant plasma concentrations and decreased efficacy
            • Corticosteroids
              • Modify dose
              • Aprepitant or fosaprepitant increases dexamethasone and methylprednisolone exposure
              • Reduce PO dexamethasone dose by ~50%
              • Reduce IV methylprednisolone dose by ~25% and PO methylprednisolone dose by ~50%
            • Benzodiazepines
              • Monitor for benzodiazepine adverse effects
              • Coadministration of aprepitant or fosaprepitant with benzodiazepines metabolized by CYP3A4 (eg, midazolam, alprazolam, triazolam) may increase benzodiazepine levels and/or effects
            • Warfarin
              • Monitor INR; adjust warfarin dose if needed
              • In patients on chronic warfarin therapy, monitor INR in the 2-week period, particularly at 7-10 days, following aprepitant or fosaprepitant administration with each chemotherapy cycle
              • Coadministration with warfarin may decrease warfarin exposure owing to induction of CYP2C9, resulting in decreases INR
            • Oral contraceptives
              • Use effective alternant or back-up methods (eg, condoms, spermicides) during treatment with aprepitant or fosaprepitant and for 1 months following administration
              • Coadministration with oral contraceptives may decrease estrogen and progestin exposure during administration and for 28 days after last aprepitant dose
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            Pregnancy & Lactation

            Pregnancy

            Data are Insufficient on use in pregnant females to inform of drug associated risk

            Animal studies

            • No adverse developmental effects observed in rats or rabbits exposed during organogenesis to systemic drug levels (AUC) ~1.5 times adult human exposure at 125-mg/80-mg/80-mg regimen

            Contraception

            • Aprepitant or fosaprepitant may reduce efficacy of hormonal contraceptives owing to induction of CYP3A4
            • Advise females of reproductive potential using hormonal contraceptives to use an effective alternative or back-up non-hormonal contraceptive (eg, condoms, spermicides) during treatment and for 1 month after last dose

            Lactation

            Unknown if excreted in milk

            Determine whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother

            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

            Fosaprepitant is a prodrug of aprepitant; its antiemetic effects are attributed to aprepitant

            Aprepitant is a selective high-affinity antagonist of human substance P/neurokinin 1 (NK1) receptors; aprepitant has little or no affinity for serotonin (5-HT3), dopamine, and corticosteroid receptors

            In animal models, aprepitant inhibited emesis induced by cytotoxic chemotherapeutic agents, such as cisplatin, via central actions

            Animal and human studies also showed aprepitant augmented antiemetic activity of the 5-HT3-receptor antagonist ondansetron and corticosteroids (eg, dexamethasone), and inhibits both acute and delayed phases of cisplatin-induced emesis

            Absorption

            Peak plasma concentration (aprepitant): 4.2 mcg/mL

            AUC (aprepitant): 37.4 mcg·hr/mL

            Fosaprepitant plasma concentrations are below the limits of quantification (10 ng/mL) within 30 minutes after completing infusion

            Distribution

            Protein bound: >95%

            Vd: 70 L

            Metabolism

            Fosaprepitant (IV form) rapidly converted to aprepitant in vivo

            Aprepitant undergoes extensive metabolism

            • Substrate of: CYP3A4 (major); CYP1A2 (minor), CYP2C19 (minor)
            • Inhibits: CYP3A4 (moderate)
            • Induces: CYP2C9 (weak) and CYP3A4 (weak)

            Elimination

            Half-life: 9-13 hr

            Total body clearance: 62-90 mL/min

            Excretion (IV admin): 57% urine; 45% feces

            Dialyzable: No

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            Administration

            IV Compatibilities

            0.9% NaCl

            IV Preparation

            Aseptically inject 5 mL 0.9% NaCl into vial along vial wall to prevent foaming

            Gently swirl to dissolve; do not shake

            Withdraw entire volume from vial and transfer it into a prepared infusion bag of 145 mL 0.9% NaCl to yield a total volume of 150 mL and a final concentration of 1 mg/mL

            Gently invert bag 2-3 times to mix

            Final volume

            • 6 months to <12 years: Calculate appropriate volume; volume to administer (mL) equals the recommended dose (mg) x weight (kg); do not exceed the maximum dose
            • 12-17 years: Calculate appropriate volume; volume to administer (mL) equals the recommended dose (mg); do not exceed the maximum dose
            • Adults: Administer entire volume of the prepared infusion bag (150 mL)
            • If necessary, for volumes <150 mL, transfer calculated volume to an appropriate size bag or syringe prior to administration by infusion

            IV Administration

            >17 years: Infuse IV over 20-30 min

            12-17 years: Infuse IV over 30 min

            6 months to <12 years: Infuse over 60 min

            Storage

            Unused vials: Refrigerate at 2-8°C (36-46°F)

            Reconstituted vials and diluted solutions: Store at room temperature at (68-77°F [20°C-25°C]) for up to 24 hr

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            Images

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            Patient Handout

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

            FormularyPatient Discounts

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

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
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            NC NOT COVERED – Drugs that are not covered by the plan.
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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.