Indinavir Dexamethasone

Clinically important, potentially hazardous interactions with atazanavir, carbamazepine, clarithromycin, dexamethasone, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, phenobarbital, phenytoin, rifabutin, rifampicin, rifampin, ritonavir, saquinavir, St John s wort, telithromycin, voriconazole... 

P-gp (ABCB1) Verapamil, digoxin, mitoxantrone, vinblastine, doxorubicin, losartan, talinolol, cortisol, dexamethasone, colchicine, loperamide, domperidone, indinavir, erythromycin, tetracycline, itraconazole, cyclosporine, methotrexate, amitryptyline, phenobarbital, morphine, cimetidine, and others... 

Drugs that might affect amprenavir include abacavir, aldesleukin, antacids, anticonvulsants, azole antifungals, clarithromycin, cyclosporine, dexamethasone, buffered didanosine, disulfiram, ethanol, indinavir, methadone, metronidazole, nelfinavir, nonnucleoside reverse transcriptase inhibitors, oral contraceptives, rifamycins, ritonavir, saquinavir, St. John s wort, tacrolimus, and zidovudine. 

Lopinavir/Ritonavir (Kaletra) [Anrirelroviral/Protease Inhibitor] Uses HIV Infxn Action Protease inhibitor Dose Adults. Tx naive 2 tab PO daily or 1 tab PO bid Tx experiencedpt 1 tab PO bid (T dose if w/ amprenavir, efavirenz, fosamprenavir, nelfinavir, nevirapine) Peds. 7-15 kg 12/3 mg/kg PO bid 15-40 kg 10/2.5 mg/kg PO bid >40 kg Adult dose w/ food Caution [C, /-] Numerous interactions Contra w/drugs dependent on CYP3A/CYP2D6 (Table VI-8) Disp Tab, soln SE Avoid disulfiram (soln has EtOH), metronidazole GI upset, asthenia, T cholesterol/triglycerides, pancreatitis protease metabolic synd Interactions T Effects Wl clarithromycin, erythromycin T effects OF amiodarone, amprenavir, azole andfungals, bepridil, cisapride, cyclosporine, CCBs, ergot alkaloids, flecainide, flurazepam, HMG-CoA reductase inhibitors, indinavir, lidocaine, meperidine, midazolam, pimozide, propafenone, propoxyphene, quinidine, rifabutin, saquinavir, sildenafil, tacrolimus, terfenadine, triazolam, zolpidem 1 effects Wl barbiturates, carbamazepine, dexamethasone, didanosine, efavirenz, nevirapine, phenytoin, rifabutin, rifampin, St. John s wort 1 effects OF OCPs, warfarin EMS Use andarrhythmics and benzodiazepines... 

Delavirdine is extensively metabolized to inactive metabolites by the CYP3A and CYP2D6 enzymes. However, it also inhibits CYP3 A and thus inhibits its own metabolism. In addition to its interactions with other antiretroviral agents (see Table 49 1), delavirdine will result in increased levels of numerous agents (Table 49-3). Dose reduction of indinavir and saquinavir should be considered if they are administered concurrently with delavirdine. Delavirdine plasma concentrations are reduced in the presence of antacids, phenytoin, phenobarbital, carbamazepine, rifabutin, and rifampin concentrations are increased during coadministration with clarithromycin, fluoxetine, dexamethasone, and ketoconazole. 

Since indinavir is a substrate as well as an inhibitor of CYP3 A4, numerous and complex drug interactions can occur as described above. Indinavir levels decrease with concurrent use of rifabutin, fluconazole, St. John s wort, and rifampin. Caution is advised with other 3 A4 inducers also, including phenobarbital, phenytoin, carbamezepine, and dexamethasone. Dose reduction of indinavir should be considered if coadministered with delavirdine, ketoconazole, or itraconazole, while an increase in the dose of indinavir is indicated if the drug is coadministered with efavirenz or rifabutin. 

Lin JH, Chiba M, Chen IW, et al. Effect of dexamethasone on the intestinal first-pass metabolism of indinavir in rats evidence of cytochrome P-450 3A and P-glycoprotein induction. Drug Metab Dispos 1999 27 1187-1193. 

Acyclovir Erythromycin Ivermectin Itraconazole Rifampin Actinomycin D Daunorubicin Doxorubicin Docetaxel Epirubicin Etoposide Imatinib Irinotecan Paclitaxel Vinblastine Vincristine Amprenavir Indinavir Nelfinavir Ritonavir Saquinavir Cyclosporine A Tacrolimus Digoxin Quinidine Verapamil Diltiazem Aldosterone Cortisol Corticosterone Dexamethasone Hydrocortisone Cyclosporine Metkephamid Enkephalin... 

Indinavir (IDV) Crixivan 100 mg, 200 mg, 333 mg, and 400 mg capsules Erythromycins, itraconazole, ketoconazole, fluconazole, tetracycline, dexamethasone... 

Clinically important, potentially hazardous interactions with amprenavir, aprepitant, bedomethasone, buprenorphine, calcium, chloramphenicol, cimetidine, dobazam, clorazepate, cyclosporine, cyproterone, darunavir, dasatinib, delavirdine, dexamethasone, diazoxide, disulfiram, dopamine, fesoterodine, fluconazole, flunisolide, fluoxetine, fosamprenavir, ginkgo biloba, hydrocortisone, imatinib, indinavir, influenza vaccines, isoniazid, isradipine, itraconazole, lacosamide, lapatinib, lopinavir, meperidine, methylprednisolone, midazolam, mivacurium, nelfinavir, nilotinib, nilutamide, phenylbutazone, piracetam, posaconazole, prednisolone, prednisone, primrose, ritonavir, rivaroxaban, sage, saquinavir, solifenacin, St John s wort, sucralfate, telithromycin, temsirolimus, teniposide, ticlopidine, tizanidine, tolvaptan, triamcinolone, uracil/tegafur, vigabatrin... 

CYP2C8 <5 1-2 Disopyramide Amiodarone Clozapine Diclofenac Fluvastatin Nicardipine Paclitaxel Retinoic acid Rosiglitazone Torsemide Repaglinide Amiodarone Celecoxib Felodipine Nicardipine Fluoxetine Ketoconazole Ritonavir Indinavir Troglitazone Zafirlukast Retinoic acid Clotrimazole Phenobarbital Dexamethasone Gemfibrozil Rifampin Phenytoin Ritonavir... 

Several cases of Cushing s syndrome have been seen in patients using inhaled or intranasal fluticasone when ritonavir was also given. Ritonavir may reduce the clearance of prednisone, and ritonavir or nelflnavir may increase levels of the active metabolite of ciclesonide. Dexamethasone may reduce the levels of indinavir and saquinavir. 

The manufacturers of dexamethasone note that it is a modest inducer of CYP3A4 and state that it may reduce the plasma levels of indinavir, and saquinavir, or other drugs metabolised by CYP3A4. The clinical outcome of this predicted effect is unknown, but until more is known, it would seem prudent to monitor antiviral efficacy if these combinations are used. 

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