Dexamethasone Aprepitant

Aprepitant, dexamethasone, or metoclopramide have demonstrated efficacy in preventing CINV, whereas the results with SSRIs are inconsistent. 

Patients receiving chemotherapy that is classified as being of high emetic risk should receive a combination antiemetic regimen containing three drugs on the day of chemotherapy administration (day 1)—an SSRI plus dexamethasone plus aprepitant. 

High SSRI + dexamethasone + aprepitant Days 2 and 3 after chemotherapy ... 

Moderate Anthracydine + cyclophosphamide SSRI (as above) and Dexamethasone 12 mg po (with aprepitant) and Aprepitant 125 mg po Aprepitant 80 mg po days 2 and 3... 

Aprepitant and dexamethasone can be used on the 2 days following administration of high emetic risk chemotherapy. 

Concomitant therapy The oral dexamethasone doses should be reduced by approximately 50% when coadministered with aprepitant. 

Aprepitant may be affected by paroxetine, CYP2C9 substrates (eg, phenytoin, tolbutamide, warfarin), CYP3A4 substrates (eg, alprazolam, cisapride, dexamethasone, docetaxel, etoposide, ifosfamide, imatinib, irinotecan, methylprednisolone, midazolam, paclitaxel, pimozide, triazolam, vinblastine, vincristine, vinorelbine), and oral contraceptives. 

Aprepitant (Emend) [Centrally Acting Antiemetic] Uses Pre-vents N/V assoc w/ emetogenic CA chemo (eg, cisplatin) (use in combo w/ other antiemetics) Action Substance P/neurokinin l(NKi) receptor antagonist Dose 125 mg PO day 1, 1 h before chemo, then 80 mg PO qAM days 2 3 Caution [B, /-] Contra Use w/ pimozide, Disp Caps SE Fatigue, asthenia, hiccups Interactions T Effects W/ clarithromycin, diltiazem, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, troleandomycin T effects OF alprazolam, astem-izole, cisapride, dexamethasone, methylprednisolone, midazolam, pimozide, terfe-nadine, triazolam, chemo agents, eg, docetaxel, etoposide, ifosfamide, imatinib, irinotecan, paclitaxel, vinblastine, vincristine, vinorelbine i effects W/ paroxetine,... 

McCrea JB, Majumdar AK, Goldberg MR, Iwamoto M, Gargano C, Panebianco DL, Hesney M, Lines CR, Petty KJ, Deutsch PJ, Murphy MG, Gottesdiener KM, Goldwater DR, Blum RA. Effects of the neurokininl receptor antagonist aprepitant on the pharmacokinetics of dexamethasone and methylprednisolone. Clin Pharmacol Ther 2003 74 17-24. 

APREPITANT ANTICANCER AND IMMUNOMODULATING DRUGS-CORTICOSTEROIDS t dexamethasone and methylprednisolone levels Inhibition of CYP3A4-mediated metabolism of these corticosteroids Be aware... 

Note Aprepitant treatment is given along with a 5-HT3-receptor antagonist and dexamethasone... 

Clinically important, potentially hazardous interactions with acetylcysteine, adenosine, aprepitant, aripiprazole, buprenorphine, caffeine, charcoal, clarithromycin, clobazam, dorazepate, clozapine, darunavir, dasatinib, delavirdine, dexamethasone, diltiazem, doxacurium, erythromycin, felodipine, fesoterodine, fosamprenavir, imatinib, influenza vaccines, lacosamide, lapatinib, levetiracetam, lopinavir, methylprednisolone, midazolam, nelfinavir, nilotinib, piracetam, prednisolone, propoxyphene, ritonavir, rivaroxaban, rufinamide, solifenacin, St John s wort, telithromycin, temsirolimus, terbinafine, tolvaptan, troleandomycin, verapamil, voriconazole... 

Clinically important, potentially hazardous interactions with amlodipine, anisindione, anticoagulants, aprepitant, atorvastatin, barbiturates, benzodiazepines, butabarbital, carbamazepine, chlordiazepoxide, clarithromycin, clonazepam, dorazepate, corticosteroids, cyclosporine, dexamethasone, diazepam, dicumarol, erythromycin, ethotoin, felodipine, flurazepam, fluvastatin, fosphenytoin, isradipine, itraconazole, ketoconazole, lorazepam, lovastatin, mephenytoin, mephobarbital, midazolam, nicardipine, nifedipine, nimodipine, nisoldipine, oxazepam, pentobarbital, phenobarbital, pimozide, pravastatin, primidone, quazepam, rifampin, secobarbital, simvastatin, St John s wort, temazepam, warfarin... 

Clinically important, potentially hazardous interactions with alfuzosin, alprazolam, amphotericin B, anisindione, antacids, aprepitant, astemizole, atorvastatin, bosentan, ciclesonide, cimetidine, clorazepate, conivaptan, cyproterone, dasatinib, dexamethasone, dicumarol, didanosine, eplerenone, erythromycin, ethotoin, fentanyl, fesoterodine, fosamprenavir, fosphenytoin, grapefruit juice, HMG-CoA reductase inhibitors, imatinib, ixabepilone, lapatinib, lopinavir, lovastatin, mephenytoin, methylprednisolone, micafungin, midazolam, nilotinib, pimozide, prednisolone, prednisone, quinidine, rifampin, rimonabant, rivaroxaban, sildenafil, silodosin, simvastatin, sirolimus, solifenacin, temsirolimus, terfenadine, tolvaptan, triazolam, vardenafil, vinblastine, vincristine, warfarin... 

Clinically important, potentially hazardous interactions with amprenavir, aprepitant, atazanavir, carbamazepine, chlorpheniramine, cimetidine, clarithromycin, clorazepate, CNS depressants, darunavir, delavirdine, dexamethasone, efavirenz, erythromycin, esomeprazole, fluconazole, fluoxetine, fosamprenavir, grapefruit juice, griseofulvin, imatinib, indinavir, itraconazole, ivermectin, ketoconazole, lopinavir, nelfinavir, nevirapine, phenobarbital, phenytoin, primidone, rifabutin, rifampin, ritonavir, roxithromycin, saquinavir, St John s wort, telithromycin, tipranavir... 

Clinically important, potentially hazardous interactions with amiodarone, amprenavir, anisindione, antacids, anticoagulants, aprepitant, atazanavir, atovaquone, beclomethasone, buprenorphine, corticosteroids, cortisone, cyclosporine, cyproterone, dabigatran, dapsone, darunavir, delavirdine, dexamethasone, dicumarol, digoxin, eszopiclone, flunisolide, fosamprenavir, gadoxetate, gestrinone, halothane, imatinib, isoniazid, itraconazole, ketoconazole, lapatinib, lorcainide, methylprednisolone, midazolam, nelfinavir, nifedipine, oral contraceptives, phenylbutazone, prednisone, protease inhibitors, pyrazinamide, ramelteon, ritonavir, saquinavir, solifenacin, sunitinib, tacrolimus, telithromycin, temsirolimus, tipranavir, tolvaptan, trabectedin, triamcinolone, triazolam, voriconazole, warfarin, zaleplon... 

After absorption, aprepitant is bound extensively to plasma proteins (>95%) it is extensively metabolized, primarily by hepatic CYP3A4, and is excreted in the stool its t is 9—13 hours. Aprepitant has the potential to interact with other substrates of CYP3A4, requiring adjustment of other drugs, including dexamethasone, methylprednisolone (whose dose may need to be reduced by 50%), and warfarin. Aprepitant is contraindicated in patients on cisapride (see above) or pimozide, in whom life-threatening ventricular tachyarrthmias has been reported. 

In a crossover study in 20 subjects, aprepitant 125 mg on day one, and 80 mg on days 2 to 5 given with a standard dexamethasone regimen (20 mg on day one, and 8 mg on days 2 to 5) increased the dexamethasone AUC by 2.2-fold. When the same dose of aprepitant was given with a reduced-dose dexamethasone regimen (12 mg on day one, and 4 mg on days 2 to 5), the AUC of dexamethasone was similar to that seen with the standard dexamethasone regimen given alone. All regimens in this study also included intravenous ondansetron 32 mg on day one. ... 

An established interaction of clinical importance. The manufacturer recommends that the usual dose of dexamethasone should be reduced by about 50% when given with aprepitant (although note that the dose given... 

Effects of die neurokininl receptor antagonist aprepitant on the pharmacokinetics of dexamethasone and methylprednisolone. Clin Pharmacol 7 ier(2003) 74,17-24. 

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