Probenecid Rifampin

Drugs that affect NSAIDs include the following Bisphosphonates, cholestyramine, cimetidine, colestipol, cyclosporine, diflunisal, DMSO, fluconazole, ketoconazole, phenobarbital, phenylbutazone, probenecid, rifampin, ritonavir, salicylates, sucralfate. 

Drugs that may affect benzodiazepines include alcohol/CNS depressants, cimetidine, oral contraceptives, disulfiram, isoniazid, probenecid, rifampin, smoking, theophyllines, and macrolides. 

Salicylates antagonize probenecid s uricosuric action. Concurrent administration of probenecid increases die effects of acyclovir, barbiturates, benzodiazepines, dap-sone, mediotrexate, NSAIDs, rifampin, and the sulfonamides. 

Drugs that may affect repaglinide include CYP 450 inhibitors (eg, clarithromycin, erythromycin, ketoconazole, miconazole), CYP 450 inducers (eg, barbiturates, carbamazepine, rifampin), beta blockers, calcium channel blockers, chloramphenicol, corticosteroids, coumarins, estrogens, gemfibrozil, isoniazid, itraconazole, levonorgestrel and ethinyl estradiol, MAOIs, nicotinic acid, NSAIDs, oral contraceptives, phenothiazines, phenytoin, probenecid, salicylates, simvastatin, sulfonamides, sympathomimetics, thiazides and other diuretics, and thyroid products. 

Drugs that may affect ACEIs may include antacids, capsaicin, indomethacin, phenothiazines, probenecid, and rifampin. Drugs that may be affected by ACEIs include allopurinol, digoxin, lithium, potassium preparations/potassium-sparing diuretics, and tetracycline. 

Drugs that may be affected by probenecid include acyclovir allopurinol barbiturates benzodiazepines clofibrate dapsone dyphylline methotrexate NSAIDs pantothenic acid penicillamine rifampin sulfonamides sulfonylureas zidovudine salicylates. 

Drugs that may affect benzodiazepines include alcohol, antacids, barbiturates, cimetidine, disulfiram, fluoxetine, isoniazid, ketoconazole, metoprolol, oral contraceptives, narcotics, probenecid, propoxyphene, propranolol, ranitidine, rifampin, scopolamine, theophylline, and valproic acid. 

Fluconazole, probenecid and atovaquone increase the risk of myelotoxicity by zidovudine. This may be attributed to an increased plasma concentration of zidovudine in the presence of these drugs, perhaps through their inhibitory effects on glucuronose transferase. Rifabutin and rifampin decrease plasma concentrations, and clarithromycin decreases the absorption of zidovudine. Zidovudine and stavu-dine should not be used in combination because they compete for intracellular phosphorylation. 

Active orally and metabolized to glucuronide conjugate—modify dose in hepatic or renal dysfunction. ZDV plasma levels are increased by azole antifungals, cimetidine, indomethacin, probenecid, and TMP-SMX—plasma levels of ZDV are decreased by rifampin. 

Probenecid but not cidofovir alters zidovudine pharmacokinetics such that zidovudine doses should be reduced when probenecid is present, as should the doses of drugs similarly affected by probenecid fe.g., /i-lactam antibiotics, nonsteroidal anti-inflammatory drugs [NSAIDs], acyclovir, lorazepam, furosemide, methotrexate, theophylline, and rifampin). Concurrent nephrotoxic agents are contraindicated, and an interval of 1 week before beginning cidofovir treatment is recommended after prior exposure to aminoglycosides, intravenous pentamidine, amphotericin foscamet, NSAIDs, or contrast dye. Cidofovir and oral ganciclovir in combination are poorly tolerated at full doses. 

BrocloneyerNH, Merlins L, Klimek K, (joos M, C inhaus EE. Comparative effects of rifampin and/cr probenecid on the phannacokinetics of temazepam and nitrazepam. IntJ Clin Pharmacol Ther Toxicol (1990) 28,387-93. 

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