Furosemide Warfarin

Kraak et al. (38) reported the first ACE application to study drug binding to a plasma protein. They used the model system warfarin-human serum albumin (HSA) to compare the suitability of the Hummel-Dreyer, frontal analysis, and vacancy peak methods. A more methodologically intended paper from Erim and Kraak (39) used VACE to study the displacement of warfarin from bovine serum albumin (BSA) by furosemide and phenylbutazone. They concluded that VACE is especially suited to examining competitive properties of simultaneously administered compounds toward a given protein-drug system. 

This study also suggests that molecular size and structure play a role in this interaction. The binding behaviors of dextrin oligomers for four different pharmaceuticals (ibuprofen, ketoprofen, furosemide, and warfarin) were observed under the same experimental conditions. Ibuprofen and ketoprofen, two compounds that are similar in chemical structure and pharmaceutical use, showed obvious differences in interaction patterns (Fig. 13A and B). Ketoprofen, having an extra aromatic ring, required an octa-saccharide (DP = 8) for binding, whereas ibuprofen required a heptasac-... 

Fig. 13 Electropherograms of amylodextrins with different pharmaceuticals. (A) ibuprofen, (B) ketoprofen, (C) furosemide, (D) warfarin. Electrophoretic conditions 20 mM phosphate buffer, pH = 7.0, ionic strength 18.3 mM. Other conditions are the same as for Figure 12. (From Ref. 75.)...

Indirect response models have been successfully applied for a number of drugs that display a relatively slow onset of effect compared to their distribution to the site of action. Examples are corticosteroids, warfarin, furosemide and terbutalin. Such models are also particularly appropriate if the measured response is a change in circulating blood cells or endogenous proteins (e.g. hormones or cytokines). 

In vitro plasma protein binding of donepezil is 96%, mainly to albumin (75%). Plasma protein binding competition with furosemide, digoxin and warfarin showed that... 

Ultrafiltration has been used to determine the protein bound fraction of many drags, such as methadone (Wilkins et al. 1997), phenylacetate and phenylbu-tyrate (Boudoulas et al. 1996), etoposide (Robieux et al. 1997), doxorubicin and vincristine (Mayer and St-Onge 1995), disopyramide (Echize et al. 1995), and ketamine and its active metabolites (Hijazi and Boulieu 2002). Schumacher et al. (2000) have shown the applicability for the determination of erythro-cyte/plasma distribution. The method of UF has been applied in the measurement of free unaltered thyroxin or after displacement by salicylate as well after displacement by heparin in healthy people and in patients with non-thyroidal somatic illness (Faber et al. 1993). The protein binding of tritium labeled, antidiabetic repaglinide and its displacement by warfarin, furosemide, tolbutamide, diazepam, glibenclamide and nicardipine were determined by ultrafiltration (Plumetal. 2000). 

E)rug5 that influence nutrient metabolism are discussed in various sections. These drugs include lovastatin, pravastatin, omeprazole, dilantin, methotrexate, allopurinol, warfarin, furosemide, thiouracil, and diphosphonatc. Alcohol is also discussed in this context because, depending on its intake, it functions as a food, drug, or toxin. 

In patients taking warfarin, furosemide, like other diuretics, reduces the prothrombin time without changing the plasma warfarin concentration (SEDA-22, 238). The reduced anticoagulant effect is probably secondary to diuretic-induced volume depletion, mediating increases in clotting factors. Any effect is hkely to be short-lived. 

Vitamin status also may be affected by drugs (Table 135-15). For example, sulfasalazine therapy has been noted to cause a decrease in folic acid, isoniazid therapy causes pyridoxine deficiency, and furosemide therapy may result in decreased thiamin concentrations. Furthermore, some drug therapy outcomes may be affected by vitamin intake. The ingestion of megadoses of folic acid may decrease methotrexate s therapeutic effect, whereas changes in an individual s usual vitamin K intake may cause variability in warfarin s anticoagulation effects. 

A 46-yr-old black female experienced an increase in INR from 2-3 to 4.05-4.9 after taking 565 mg of dong quai once or twice daily for 4 wk. The patient s past medical history included rheumatic heart disease, stroke, and atrial fibrillation. Medications included 5 mg/d of warfarin, 0.25 mg/d of digoxin, and 20 mg/d of furosemide. Upon dechallenge from dong quai, her... 

Indomethacin does not directly modify the effect of warfarin, but platelet inhibition and gastric irritation increase the risk of bleeding concurrent administration is not recommended. Indomethacin antagonizes the natriuretic and antihypertensive effects of furosemide and thiazide diuretics and blunts the antihypertensive effect of 13-receptor antagonists, ATj-receptor antagonists, and ACE inhibitors. 

Cronqvist, J. Nilsson-Ehle, I. Determination of acyclovir in human serum hy hi -performance liquid chromatography. J.Liq.Chromatogr., 1988, 11, 2593-2601 [serum non-interfering acetaminophen, allopurinol, baclofen, carbacholine, cefuroxime, chlorpropamide, cilastatin, cloxacillin, diazepam, di-cumarol, digoxin, flucloxacillm, furosemide, fusidic acid, fusidic, glipizide, heparin, hydrochlorothiazide, imipenem, insulin, isoniazid, ketoprofen, metronidazole, naproxen, perphenazine, phenytoin, prednisolone, propranolol, p3razinamide, p3ridoxine, ranitidine, rifampicin, rifampin, spironolactone, streptomycin, sulfamethoxazole, trimethoprim, warfarin]... 

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