Drug Facts
Composition & Profile
Identifiers & Packaging
16 HOW SUPPLIED/STORAGE AND HANDLING No. 034 —Single-dose glass vial containing 150 mg of fosaprepitant as a white to off white lyophilized cake or powder for reconstitution. Supplied as follows: NDC43598-859-11 1 vial per carton. StorageFosaprepitant for injection vials must be refrigerated, store at 2°C - 8°C(36°F - 46°F).The reconstituted final drug solution is stable for 24 hours at ambient room temperature [at or below 25°C (77°F)].; PACKAGE LABEL PRINCIPAL DISPLAY PANEL SECTION Vial Label:; Carton label: Unvarnished Area Consists of: 2D Barcode, Lot Number, Expiry Date and Serial Number
- 16 HOW SUPPLIED/STORAGE AND HANDLING No. 034 —Single-dose glass vial containing 150 mg of fosaprepitant as a white to off white lyophilized cake or powder for reconstitution. Supplied as follows: NDC43598-859-11 1 vial per carton. StorageFosaprepitant for injection vials must be refrigerated, store at 2°C - 8°C(36°F - 46°F).The reconstituted final drug solution is stable for 24 hours at ambient room temperature [at or below 25°C (77°F)].
- PACKAGE LABEL PRINCIPAL DISPLAY PANEL SECTION Vial Label:
- Carton label: Unvarnished Area Consists of: 2D Barcode, Lot Number, Expiry Date and Serial Number
Overview
Fosaprepitant for injection is a sterile, lyophilized formulation containing fosaprepitant dimeglumine,a prodrug of aprepitant a substance P/neurokinin-1 (NK 1 ) receptor antagonist, an antiemetic agent, chemically described as 1 Deoxy-1-(methylamino)-D-glucito[3-[[(2R,3S)-2-[(1R)-1-[3,5- bis(trifluoromethyl)phenyl]ethoxy]-3-(4 fluorophenyl)-4-morpholinyl]methyl]-2,5-dihydro-5-oxo-1H-1,2,4-triazol-1-yl]phosphonate(2:1) (salt).Its empirical formula is C 23 H 22 F 7 N 4 O 6 P • 2(C 7 H 17 NO 5 ) and its structural formula is: Fosaprepitant dimeglumine is a white to off-white powder with a molecular weight of 1004.83. It is freely soluble in water soluble in N,N-Dimethylsulfoxide and insoluble in n-hexane.Each vial of fosaprepitant for injection for administration as an intravenous infusion contains 245.3 mg of fosaprepitant dimeglumine equivalent to 150 mg of fosaprepitant free acid and the following inactive ingredients: edetatedisodium (18.8 mg), lactose anhydrous(375 mg), polysorbate 80 (75 mg), sodium hydroxide and/orhydrochloric acid (for pH adjustment).
Indications & Usage
Fosaprepitant for injection, in combination with other antiemetic agents, is indicated in adults for the prevention of: acute and delayed nauseaand vomiting associated with initial and repeat coursesof 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). Limitations of Use Fosaprepitant for injection has not been studied for the treatment of established nausea and vomiting. Pediatric use information is approved for Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s Emend (fosaprepitant) for injection. However, due to Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. Fosaprepitant for injection is a substance P/neurokinin-1 (NK 1 ) receptor antagonist, indicated in adults, in combination with other antiemetic agents, for the prevention of ( 1 ): acute and delayed nausea and vomiting associated with initial and repeat coursesof 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). Limitations of Use ( 1 ) Fosaprepitant for injection has not been studied for treatment of established nausea and vomiting.
Dosage & Administration
Recommended Dosage ( 2.1 ) Adults: 150 mg on Day 1.Administer fosaprepitant for injection on Day 1 as an intravenous infusion over 20 to 30 minutes (adults), completing the infusion approximately 30 minutes prior to chemotherapy. See Full Prescribing Information for dosages of concomitantantiemetic(s). ( 2.1 ) 2.1 Prevention of Nausea and Vomiting Associated with HEC and MEC in Adult Patients The recommended dosage of fosaprepitant for injection, dexamethasone, and a 5-HT 3 antagonist for the prevention of nausea and vomiting associated with administration of HEC or MEC in adults is shown in Table 1 or Table 2, respectively. Administer fosaprepitant for injectionas an intravenous infusion on Day 1 over 20 to 30 minutes, completing the infusion approximately 30 minutes priorto chemotherapy. Table 1 Recommended Adult Dosing for the Prevention of Nausea and Vomiting Associated with HEC Day 1 Day 2 Day 3 Day 4 Fosaprepitant for injection 150 mgintravenouslyover 20 to 30 minutesapproximately 30 minutes prior to chemotherapy none none none Dexamethasone * 12 mg orally 8 mg orally 8 mg orally twice daily 8 mg orally twice daily 5-HT 3 antagonist See selected 5-HT 3 antagonist prescribing information for the recommended dosage none none none * Administer dexamethasone 30 minutes prior to chemotherapy treatment on Day 1 and in the morning on Days 2 through 4. Also administer dexamethasone in the evenings on Days 3 and 4. A 50% dosage reduction of dexamethasone on Days 1 and 2 is recommended to account for a drug interaction with fosaprepitant for injection [see ClinicalPharmacology (12.3)]. Table 2 Recommended Adult Dosing for the Prevention of Nausea and Vomiting Associated with MEC Day 1 Fosaprepitant for injection 150 mg intravenously over 20 to 30 minutes approximately 30 minutes prior to chemotherapy Dexamethasone * 12 mg orally 5-HT 3 antagonist See selected 5-HT 3 antagonist prescribing information for the recommended dosage * Administer dexamethasone 30 minutes prior to chemotherapy treatment on Day 1. A 50% dosage reduction of dexamethasone is recommended to account for a drug interaction with fosaprepitant dimeglumine [see Clinical Pharmacology (12.3)]. Pediatric use information is approved for Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s Emend (fosaprepitant) for injection. However, due to Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. 2.3 Preparation of Fosaprepitant for Injection Table 5 Preparation Instructions for Fosaprepitant for Injection (150 mg) Step 1 Aseptically inject 5 mL 0.9% Sodium Chloride Injection, USP into the vial. Assure that 0.9% Sodium Chloride Injection, USP is added to the vial along the vial wall in order to prevent foaming. Swirl the vial gently. Avoid shaking and jetting 0.9% Sodium Chloride Injection, USP into the vial. Step 2 Aseptically prepare an infusion bag filled with 145 mL of 0.9% Sodium Chloride Injection, USP. Step 3 Aseptically withdraw the entire volume from the vial and transfer it into the infusion bag containing 145 mL of 0.9% Sodium Chloride Injection, USP to yield a total volume of 150 mL and a final concentration of 1 mg/mL . Step 4 Gently invert the bag 2 to 3 times. Step 5 AdultsThe entire volume of the prepared infusion bag (150 mL) should be administered. Step 6 Before administration, inspect the bag for particulate matter and discoloration. Discard the bag if particulate and/or discoloration are observed. Caution: Do not mix or reconstitute fosaprepitant for injection with solutions for which physicaland chemical compatibility have not been established. Fosaprepitant for injection is incompatible with any solutions containing divalent cations (e.g., Ca 2+ , Mg 2+ ), including Lactated Ringer’s Solution and Hartmann's Solution.Storage The reconstituted final drug solution is stable for 24 hours at ambient room temperature [at or below 25°C (77°F)]. Pediatric use information is approved for Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s Emend (fosaprepitant) for injection. However, due to Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information.
Warnings & Precautions
CYP3A4 Interactions: Fosaprepitant is a weak inhibitor of CYP3A4, and aprepitant, the active moiety, is a substrate, inhibitor, and inducer of CYP3A4; see Full Prescribing Information for recommendations regarding contraindications, risk of adverse reactions, and dosage adjustment of fosaprepitant and concomitant drugs. ( 4 , 5.1 , 7.1 , 7.2 ) Hypersensitivity Reactions (including anaphylaxis and anaphylactic shock): May occur during or soon after infusion; if symptoms occur, discontinue the drug. Do not reinitiate fosaprepitant if symptoms occur with previous use. (4 , 5.2 ) Infusion Site Reactions (including thrombophlebitis, necrosis, and vasculitis): Majority of reactions reported in patients receiving vesicant chemotherapy. Avoid infusion into small veins. Discontinue infusion and administer treatment if a severe reaction develops. ( 5.3 ) Warfarin (a CYP2C9 substrate): Risk of decreased INR of prothrombin time; monitor INR in 2–week period, particularly at 7 to 10 days, following initiation of fosaprepitant. ( 5.4 , 7.1 ) Hormonal Contraceptives: Efficacy of contraceptives may be reduced during and for 28 days following administration of fosaprepitant. Use effective alternative or back-up methods of contraception. ( 5.5 , 7.1 , 8.3 ) 5.1 Clinically Significant CYP3A4 Drug Interactions Fosaprepitant, a prodrug of aprepitant, is a weak inhibitor of CYP3A4, and aprepitant is a substrate, inhibitor, and inducer of CYP3A4. Use of fosaprepitant with other drugs that are CYP3A4 substrates, may result in increased plasma concentration of the concomitant drug. o Use of pimozidewith fosaprepitant is contraindicated due to the risk of significantly increased plasma concentrations of pimozide, potentially resulting in prolongation of the QT interval, a known adverse reactionof pimozide [seeContraindications (4)]. Use of Fosaprepitant with strong or moderate CYP3A4 inhibitors (e.g., ketoconazole, diltiazem) may increase plasma concentrations of aprepitant and result in an increased risk of adversereactions related to fosaprepitant. Use of fosaprepitant with strong CYP3A4 inducers(e.g., rifampin) may result in a reductionin aprepitant plasma concentrations and decreased efficacy of fosaprepitant.See Table 7 and Table 8 for a listing of potentially significant drug interactions [see Drug Interactions ( 7.1 , 7.2 )]. 5.2 Hypersensitivity Reactions Serious hypersensitivity reactions, including anaphylaxis and anaphylactic shock, during or soon after infusionof fosaprepitant have occurred. Symptoms including flushing, erythema,dyspnea, hypotension and syncope have been reported [see Adverse Reactions (6.2)]. Monitor patients during and after infusion. If hypersensitivity reactions occur, discontinue the infusion and administer appropriate medicaltherapy. Do not reinitiate fosaprepitant in patients who experience thesesymptoms with previous use [see contraindications (4)]. 5.3 Infusion Site Reaction Infusion site reactions (ISRs) have been reported with the use of fosaprepitant for injection [see Adverse Reactions (6.1) ] . The 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 in some patients with concomitant vesicant chemotherapy. Most ISRs occurred with the first, second or third exposure to single doses of fosaprepitant for injection and in some cases, reactions persisted for two weeks or longer. Treatment of severe ISRs consisted of medical, and in some cases surgical, intervention. Avoid infusion of fosaprepitant for injection into small veins or through a butterfly catheter. If a severe ISR develops during infusion, discontinue the infusion and administer appropriate medical treatment. 5.4 Decrease in INR with Concomitant Warfarin Coadministration of fosaprepitant with warfarin, a CYP2C9 substrate, may result in a clinically significant decrease in the International Normalized Ratio (INR) of prothrombin time [see Clinical Pharmacology (12.3) ] . Monitor the INR in patients on chronic warfarin therapy in the 2-week period, particularly at 7 to 10 days, following initiation of fosaprepitant with each chemotherapy cycle [see Drug Interactions (7.1) ] . 5.5 Risk of Reduced Efficacy of Hormonal Contraceptives Upon coadministration with fosaprepitant, the efficacy of hormonal contraceptives may be reduced during administration of and for 28 days followingthe last dose of fosaprepitant [see ClinicalPharmacology (12.3) ] . Advise patients to use effective alternative or back-up methods of contraception during treatment with fosaprepitant and for 1 month following administration of fosaprepitant [see Drug Interactions (7.1) , Use in Specific Populations (8.3) ] . 5.4 Decrease in INR with Concomitant Warfarin Coadministration of fosaprepitant with warfarin, a CYP2C9 substrate, may result in a clinically significant decrease in the International Normalized Ratio (INR) of prothrombin time [see Clinical Pharmacology (12.3) ] . Monitor the INR in patients on chronic warfarin therapy in the 2-week period, particularly at 7 to 10 days, following initiation of fosaprepitant with each chemotherapy cycle [see Drug Interactions (7.1) ] .
Contraindications
Fosaprepitant is contraindicated in patients: who are hypersensitive to any component of the product Hypersensitivity reactions includinganaphylactic reactions, flushing, erythema, and dyspnea have been reported [see Warnings and Precautions ( 5.2 ), Adverse Reactions ( 6.2 )]. taking pimozide. Inhibition of CYP3A4 by aprepitant, the active moiety,could result in elevated plasma concentrations of this drug, which is a CYP3A4 substrate, potentially causing serious or life- threatening reactions, such as QT prolongation, a known adverse reaction of pimozide [see Warnings and Precautions( 5.1 )]. Known hypersensitivity to any component of this drug. ( 4 , 5.2 ) Concurrent use with pimozide. ( 4 )
Adverse Reactions
The following clinically significant adverse reactions are described elsewhere in the labeling: Hypersensitivity Reactions [see Warnings and Precautions (5.2) ] Infusion Site Reactions [see Warnings and Precautions (5.3) ] Most common adverse reactions in adults (≥2%) are: fatigue, diarrhea, neutropenia, asthenia, anemia, peripheral neuropathy, leukopenia, dyspepsia, urinary tract infection, pain in extremity. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, Dr. Reddy’s Laboratories Inc., at 1-888-375-3784 at 1-848-200-1906 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The overall safety of fosaprepitant for injection was evaluated in approximately 1600 adult patients. Adverse Reactions in Adults for the Prevention of Nausea and Vomiting Associated with MEC In an active-controlled clinical trial in patients receiving MEC, safety was evaluated in 504 patients receiving a single dose of fosaprepitant for injection in combination with ondansetron and dexamethasone (fosaprepitant dimeglumine regimen) compared to 497 patients receiving ondansetron and dexamethasone alone (standard therapy). The most common adverse reactions are listed in Table 6. Table 6 Most Common Adverse Reactions in Patients Receiving MEC * Fosaprepitant for injection, ondansetron, and dexamethasone † (N=504) Ondansetron and dexamethasone ‡ (N=497) fatigue 15% 13% diarrhea 13% 11% neutropenia 8% 7% asthenia 4% 3% anemia 3% 2% peripheral neuropathy 3% 2% leukopenia 2% 1% dyspepsia 2% 1% urinary tract infection 2% 1% pain in extremity 2% 1% * Reported in ≥2% of patients treated with the fosaprepitant dimeglumine regimen and at a greater incidence than standard therapy. † fosaprepitant dimeglumine regimen ‡ Standard therapy Infusion-site reactions were reported in 2.2% of patients treated with the fosaprepitant dimeglumine regimen compared to 0.6% of patients treated with standard therapy. The infusion-site reactions included: infusion-site pain (1.2%, 0.4%), injection-site irritation (0.2%, 0.0%), vessel puncture-site pain (0.2%, 0.0%), and infusion-site thrombophlebitis (0.6%, 0.0%), reported in the fosaprepitant dimeglumine regimen compared to standard therapy, respectively. Adverse Reactions in Adults for the Prevention of Nausea and Vomiting Associated with HEC In an active-controlled clinical study in patients receiving HEC, safety was evaluated for 1143 patients receiving a single dose of fosaprepitant for injection compared to 1169 patientsreceiving the 3-day regimen of oral aprepitant [see Clinical Studies (14.1) ] . The safety profile was generallysimilar to that seen in the MEC study with fosaprepitant and prior HEC studies with aprepitant. However,infusion- site reactionsoccurred at a higher incidence in patients in the fosaprepitant group (3.0%) comparedto those in the aprepitant group (0.5%). The following additional infusion-site reactions occurredin HEC study and were not reportedin the MEC study describedabove: infusion-site erythema(0.5%, 0.1%), infusion-site pruritus (0.3%, 0.0%), and infusion-site induration (0.2%, 0.1%), reported in the fosaprepitant group compared to the aprepitant group, respectively.Because fosaprepitant is converted to aprepitant, those adverse reactions associated with aprepitant might also be expected to occur with fosaprepitant for injection. See the full prescribing information for aprepitant capsules for complete safety information regarding studies performed with oral aprepitant. Pediatric use information is approved for Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s Emend (fosaprepitant) for injection. However, due to Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of fosaprepitant. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possibleto reliably estimatetheir frequency or establish a causal relationship to drug exposure. Skin and subcutaneous tissue disorders: pruritus, rash, urticaria, Stevens-Johnson syndrome/toxic epidermalnecrolysis. [see Warnings and Precautions (5.2) ] . Immune system disorders: hypersensitivity reactions including anaphylaxis and anaphylactic shock [see Contraindications (4) , Warnings and Precautions (5.2) ] . Nervous system disorders: ifosfamide-induced neurotoxicity reported after fosaprepitant and ifosfamide coadministration. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The overall safety of fosaprepitant for injection was evaluated in approximately 1600 adult patients. Adverse Reactions in Adults for the Prevention of Nausea and Vomiting Associated with MEC In an active-controlled clinical trial in patients receiving MEC, safety was evaluated in 504 patients receiving a single dose of fosaprepitant for injection in combination with ondansetron and dexamethasone (fosaprepitant dimeglumine regimen) compared to 497 patients receiving ondansetron and dexamethasone alone (standard therapy). The most common adverse reactions are listed in Table 6. Table 6 Most Common Adverse Reactions in Patients Receiving MEC * Fosaprepitant for injection, ondansetron, and dexamethasone † (N=504) Ondansetron and dexamethasone ‡ (N=497) fatigue 15% 13% diarrhea 13% 11% neutropenia 8% 7% asthenia 4% 3% anemia 3% 2% peripheral neuropathy 3% 2% leukopenia 2% 1% dyspepsia 2% 1% urinary tract infection 2% 1% pain in extremity 2% 1% * Reported in ≥2% of patients treated with the fosaprepitant dimeglumine regimen and at a greater incidence than standard therapy. † fosaprepitant dimeglumine regimen ‡ Standard therapy Infusion-site reactions were reported in 2.2% of patients treated with the fosaprepitant dimeglumine regimen compared to 0.6% of patients treated with standard therapy. The infusion-site reactions included: infusion-site pain (1.2%, 0.4%), injection-site irritation (0.2%, 0.0%), vessel puncture-site pain (0.2%, 0.0%), and infusion-site thrombophlebitis (0.6%, 0.0%), reported in the fosaprepitant dimeglumine regimen compared to standard therapy, respectively. Adverse Reactions in Adults for the Prevention of Nausea and Vomiting Associated with HEC In an active-controlled clinical study in patients receiving HEC, safety was evaluated for 1143 patients receiving a single dose of fosaprepitant for injection compared to 1169 patientsreceiving the 3-day regimen of oral aprepitant [see Clinical Studies (14.1) ] . The safety profile was generallysimilar to that seen in the MEC study with fosaprepitant and prior HEC studies with aprepitant. However,infusion- site reactionsoccurred at a higher incidence in patients in the fosaprepitant group (3.0%) comparedto those in the aprepitant group (0.5%). The following additional infusion-site reactions occurredin HEC study and were not reportedin the MEC study describedabove: infusion-site erythema(0.5%, 0.1%), infusion-site pruritus (0.3%, 0.0%), and infusion-site induration (0.2%, 0.1%), reported in the fosaprepitant group compared to the aprepitant group, respectively.Because fosaprepitant is converted to aprepitant, those adverse reactions associated with aprepitant might also be expected to occur with fosaprepitant for injection. See the full prescribing information for aprepitant capsules for complete safety information regarding studies performed with oral aprepitant. Pediatric use information is approved for Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s Emend (fosaprepitant) for injection. However, due to Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of fosaprepitant. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possibleto reliably estimatetheir frequency or establish a causal relationship to drug exposure. Skin and subcutaneous tissue disorders: pruritus, rash, urticaria, Stevens-Johnson syndrome/toxic epidermalnecrolysis. [see Warnings and Precautions (5.2) ] . Immune system disorders: hypersensitivity reactions including anaphylaxis and anaphylactic shock [see Contraindications (4) , Warnings and Precautions (5.2) ] . Nervous system disorders: ifosfamide-induced neurotoxicity reported after fosaprepitant and ifosfamide coadministration.
Drug Interactions
See Full Prescribing Information for a list of clinicallysignificant drug interactions. ( 4 , 5.1 , 5.4 , 5.5 , 7.1 , 7.2 ) Pediatric use information is approved for Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s Emend (fosaprepitant) for injection. However, due to Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. 7.1 Effect of Fosaprepitant/Aprepitant on the Pharmacokinetics of Other Drugs When administered intravenously, fosaprepitant, a prodrug of aprepitant, is converted to aprepitant within 30 minutes.Therefore, drug interactions following administration of fosaprepitant for injection are likely to occur with drugs that interact with oral aprepitant. Fosaprepitant, given as a single 150-mg dose, is a weak inhibitor of CYP3A4, and the weak inhibition of CYP3A4 continues for 2 days after single dose administration. Single dose fosaprepitant does not induce CYP3A4. Aprepitant is a substrate, an inhibitor, and an inducer of CYP3A4. Aprepitant is also an inducerof CYP2C9 [seeClinical Pharmacology (12.3) ] . Some substrates of CYP3A4 are contraindicated with fosaprepitant [see Contraindications (4) ] . Dosage adjustment of some CYP3A4 and CYP2C9 substrates may be warranted, as shown in Table 7. Table 7 Effects of Fosaprepitant/Aprepitant on the Pharmacokinetics of Other Drugs CYP3A4 Substrates Pimozide Clinical Impact Increased pimozide exposure Intervention Fosaprepitant is contraindicated [see Contraindications (4) ] . Benzodiazepines Clinical Impact Increased exposure to midazolam or other benzodiazepines metabolized via CYP3A4(alprazolam, triazolam) may increase the risk of adverse reactions [see Clinical Pharmacology (12.3) ]. Intervention Monitor for benzodiazepine-related adverse reactions. Dexamethasone Clinical Impact Increased dexamethasone exposure [see Clinical Pharmacology (12.3) ] . Intervention Reducethe dose of oral dexamethasone by approximately 50% [see Dosageand Administration (2.1) ] . Methylprednisolone Clinical Impact Increased methylprednisolone exposure [see Clinical Pharmacology (12.3) ] . Intervention Reduce the dose of oral methylprednisolone by approximately 50% on Days 1 and 2 for patients receiving HEC and on Day 1 for patients receiving MEC.Reduce the dose of intravenous methylprednisolone by 25% on Days 1 and 2 for patients receiving HEC and on Day 1 for patients receiving MEC. Chemotherapeutic agents that are metabolized by CYP3A4 Clinical Impact Increased exposure of the chemotherapeutic agentmay increase the risk of adverse reactions [see Clinical Pharmacology (12.3) ] . Intervention Vinblastine, vincristine, or ifosfamide or other chemotherapeutic agentsMonitor for chemotherapeutic-related adverse reactions.Etoposide, vinorelbine, paclitaxel, and docetaxelNo dosage adjustment needed. Hormonal Contraceptives Clinical Impact Decreased hormonal exposure duringadministration of and for 28 days after administration of the last dose of fosaprepitant [see Warnings and Precautions (5.5) , Use in Specific Populations (8.3) , and Clinical Pharmacology (12.3) ]. Intervention Effective alternative or back-up methods of contraception (such as condoms and spermicides) should be used during treatment with fosaprepitant and for 1 month following administration of fosaprepitant. Examples birth control pills, skin patches, implants, and certain IUDs CYP2C9 Substrates Warfarin Clinical Impact Decreased warfarin exposure and prolongation of prothrombin time (INR) [see Warnings and Precautions (5.4) , Clinical Pharmacology (12.3) ] . Intervention In patients on chronic warfarin therapy, monitor the prothrombin time(INR) in the2-week period, particularly at 7 to 10 days, following administration of fosaprepitant with each chemotherapy cycle. Other 5-HT 3 Antagonists Clinical Impact No change in the exposure of the 5-HT 3 antagonist [see Clinical Pharmacology (12.3) ] . Intervention No dosage adjustment needed Examples ondansetron, granisetron, dolasetron 7.2 Effect of Other Drugs on the Pharmacokinetics of Fosaprepitant/Aprepitant Aprepitant is a CYP3A4 substrate [see Clinical Pharmacology (12.3) ] . Co-administration of fosaprepitant with drugs that are inhibitors or inducers of CYP3A4 may result in increased or decreased plasma concentrations of aprepitant, respectively, as shown in Table 8. Table 8 Effects of Other Drugs on Pharmacokinetics of Fosaprepitant/Aprepitant Moderate to Strong CYP3A4 Inhibitors Clinical Impact Significantly increased exposure of aprepitant may increase the risk of adverse reactions associated with fosaprepitant [see Adverse Reactions (6.1) and Clinical Pharmacology (12.3) ] . Intervention Avoid concomitant use of fosaprepitant Examples Moderate inhibitor: diltiazemStrong inhibitors:ketoconazole, itraconazole, nefazodone, troleandomycin, clarithromycin, ritonavir, nelfinavir Strong CYP3A4Inducers Clinical Impact Substantially decreased exposure of aprepitant in patients chronically taking a strong CYP3A4 inducer may decrease the efficacy of fosaprepitant [see Clinical Pharmacology (12.3) ] . Intervention Avoid concomitant use of fosaprepitant. Examples rifampin, carbamazepine, phenytoin
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