Itraconazole Antacids

The gastrointestinal absorption of ketoconazole is markedly reduced by antacids. Itraconazole may also be modestly affected. However, the absorption of fluconazole and posaconazole appears not be to significantly affected by antacids. Similarly, voriconazole is not expected to be affected. 

The location of the tip of the feeding tube is important when considering medication administration down a feeding tube. This is particularly true if the medication acts locally in the GI tract itself. For example, sucralfate and antacids act locally in the stomach. Therefore, administration of these medications through a duodenal or jejunal tube is not logical. Likewise, for medications such as itraconazole that require acid for best absorption, administration directly into the duodenum or jejunum would be expected to result in suboptimal absorption. Absorption of drugs when administered directly into the small bowel, especially the jejunum, rather than into the stomach is another area where more research would be useful. 

Decreased gastric acidity Under fasted conditions, itraconazole absorption was decreased in the presence of decreased gastric acidity. The absorption of itraconazole may be decreased with coadministration of antacids or gastric acid secretion suppressors. Studies conducted under fasted conditions demonstrated that administration with 8 oz of a cola beverage resulted in increased absorption of itraconazole in AIDS patients with relative or absolute achlorhydria. This increase relative to the effects of a full meal is unknown. 

Drugs that may affect itraconazole include antacids, carbamazepine, didanosine, H2 antagonists, hydantoins, macrolide antibiotics, nevirapine, phenobarbital, phenytoin, protease inhibitors, proton pump inhibitors, and rifamycins. 

Drugs that may affect atazanavir include the following antacids and buffered medications, clarithromycin, didanosine (buffered formulation only), efavirenz, H2-receptor antagonists, indinavir, itraconazole, ketoconazole, nevirapine, proton pump inhibitors, rifampin, ritonavir, St. John s wort, tenofovir, voriconazole. 

NA /D, abd pain, bleeding, fevCT, T QT Interactions t Effects W7 atazanavir, clarithromycin, CT5rthromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfi-navir, ritonavir, saquinavir, telithromycin X effects W7 antacids, carbamazqjine, dexamethasone, phenobarbital, phenytoin, rifampicin, St. John s wort EMS Drug contains lactose, may cause D/abd discomfort in pts w/ lactose intolerance OD Sxs unknown symptomatic and supportive... 

Itraconazole has significant interactions with a number of commonly prescribed drugs, such as rifampin, phenytoin, and carbamazepine. Itraconazole raises serum digoxin and cyclosporine levels and may affect the metabolism of oral hypoglycemic agents and coumadin. Absorption of itraconazole is impaired by antacids, Hj blockers, proton pump inhibitors, and drugs that contain buffers, such as the antiretroviral agent didanosine. 

With the important exception of additive effects when combined with other CNS depressants, including alcohol, BZDs interact with very few drugs. Disulfiram (see the section The Alcoholic Patient in Chapter 14) and cimetidine may increase BZD blood levels, and diazepam may increase blood levels of digoxin and phenytoin. Antacids may reduce the clinical effects of clorazepate by hindering its biotransformation to desmethyidiazepam. Coadministration of a BZD and another drug known to induce seizures may possibly increase seizure risk, especially if the BZD is abruptly withdrawn. Furthermore, as noted earlier, important interactions have been reported among nefazodone, erythromycin, troleandomycin, and other macrolide antibiotics, as well as itraconazole. In each case, metabolism is inhibited, and triazolam levels can increase significantly. 

Drug Interactions Gemfibrozil Niacin Erythromycin Cholestyramine Digoxin Cimetidine/ranitidine/ omeprazole Rifampicin Warfarin Itraconazole Gemfibrozil Niacin Erythromycin Propranolol Digoxin Warfarin Antacids Colestipol Digoxin Erythromycin Oral contraceptives Fibrates Niacin Azole antifungals... 

Famotidine-OTC antacids and antifungal drugs (ketoconazole, itraconazole)... 

AZOLES ANTACIDS i plasma concentration of itraconazole and ketoconazole, with risk of therapeutic failure Itraconazole absorption in capsule form requires an acidic gastric environment and thus absorption would l Separate administration of agents that i gastric acidity by 1-2 hours. However, absorption of itraconazole liquid solution does not require an acidic environment and could be used instead it does not need to be given with food. Fluconazole absorption is not pH dependent, and this is a suitable alternative... 

Itraconazole is an orally active, broad-spectrum antifungal agent that has become an important alternative to kettK ona-zole. An acidic environment is requited for optimum solubi-lizoitinn and oral absorption of itraconazole. Drugs such as H2-hi.staminc antagonists and antacid.s, which reduce stomach acidity, reduce its gastrointestinal absorption. Food... 

Clinically important, potentially hazardous interactions with aminophylline, amprenavir, antacids, carbamazepine, carmustine, chlorpheniramine, clarithromycin, efavirenz, esomeprazole, imatinib, indinavir, itraconazole, ketoconazole, MAO inhibitors, midazolam, modobemide, nelfinavir, phenytoin, sucralfate, warfarin... 

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... 

For mention of a study in which some patients needed an increase in itraconazole dose when treated with ranitidine and an antacid [not named], see Azoles + H2-receptor antagonists , p.217. 

The sifuafion wifh itraconazole is not entirely clear, but based on the data with H2-receptor antagonists , (p.217), some reduction in its absorption might be expected with antacids, and it would therefore be prudent to separate administration. 

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