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Japanese Journal of Pharmacology Feb 1979Metolazone, the sulfonamide diuretic was investigated to determine the sites of action. We used a radioactive microsphere, clearance and stop-flow method in anesthetized...
Metolazone, the sulfonamide diuretic was investigated to determine the sites of action. We used a radioactive microsphere, clearance and stop-flow method in anesthetized dogs. Urine flow and urinary excretion of sodium and potassium were increased at 5--60 min when metolazone was given intravenously at doses of 0.2--5.0 mg/kg, while total renal blood flow, distribution of cortical renal blood flow and GFR did not change. The urinary excretion rate of sodium to potassium (Na/K) increased from 5.69 +/- 0.82 to 8.07 +/- 0.76 in a dose of 1.0 mg/kg, i.v. Osmolar clearance and free water reabsorption increased almost proportionally, indicating that metolazone has little effect on the medullary portion of the ascending limb of Henle and may have a proximal site of action. In stop-flow experiments, a significantly raised U/PNa/U/Pcreatinine was observed at the dip situated distally to the ascending limb of Henle. These findings indicate that the diuretic action of metolazone may be due to the inhibition of sodium reabsorption in the distal nephron segments, in addition to the absence of modification of the cortical regional blood flow.
Topics: Animals; Binding Sites; Blood Flow Velocity; Diuretics; Dogs; Female; Glomerular Filtration Rate; Hemodynamics; Injections, Intravenous; Kidney; Male; Metolazone; Potassium; Sodium; Urodynamics
PubMed: 459149
DOI: 10.1254/jjp.29.113 -
British Medical Journal (Clinical... Dec 1981
Topics: Adult; Diuretics; Drug Synergism; Female; Furosemide; Humans; Metolazone
PubMed: 6796191
DOI: 10.1136/bmj.283.6306.1611-a -
British Medical Journal Oct 1972Metolazone is a modified quinazolinesulphonamide and in a dose of between 4 and 7.5 mg is an effective diuretic in man with normal renal function. Fourteen patients with... (Clinical Trial)
Clinical Trial
Metolazone is a modified quinazolinesulphonamide and in a dose of between 4 and 7.5 mg is an effective diuretic in man with normal renal function. Fourteen patients with non-oedematous stable chronic renal failure (creatinine clearance ranging from 1.2 to 12 ml/min) were given metolazone in doses ranging from 20-150 mg. A noticeable increase in urine flow and sodium excretion occurred, free water clearance increased, and there was a small but significant increase in potassium excretion. No side effects were noted.
Topics: Adolescent; Adult; Aged; Animals; Creatinine; Diuretics; Female; Glomerulonephritis; Humans; Ketones; Kidney Failure, Chronic; Male; Middle Aged; Osmolar Concentration; Polycystic Kidney Diseases; Potassium; Pyelonephritis; Quinazolines; Sodium; Sulfonamides; Urination
PubMed: 5082545
DOI: 10.1136/bmj.4.5834.196 -
Case Reports in Cardiology 2013Diuretics, including furosemide, metolazone, and spironolactone, have historically been the mainstay of therapy for acute decompensated heart failure patients. The...
Diuretics, including furosemide, metolazone, and spironolactone, have historically been the mainstay of therapy for acute decompensated heart failure patients. The addition of an aquaretic-like vasopressin antagonist may enhance diuresis further. However, clinical experience with this quadruple combination is lacking in the acute setting. We present two hospitalized patients with acute decompensated heart failure due to massive fluid overload treated with a combination strategy of triple diuretics in conjunction with the aquaretic tolvaptan. The first patient lost 72.1 lbs. (32.7 kg) with an average urine output of 3.5 to 7.5 L/day over eight days on combined therapy with furosemide, metolazone, spironolactone, and tolvaptan. The second patient similarly achieved a weight loss of 28.2 lbs. (12.8 kg) over 4 days on the same treatment. Both patients maintained stable serum sodium, potassium, and creatinine over this period and remained out of the hospital for more than 30 days. Thus, patients hospitalized with acute decompensated heart failure due to volume overload can achieve euvolemia rapidly and without electrolytes disturbances using this regimen, while being under the close supervision of a team of cardiologists and nephrologists. Additionally, this therapy can potentially decrease the need for ultrafiltration and the length of hospital stay.
PubMed: 24829808
DOI: 10.1155/2013/750794 -
Scientia Pharmaceutica 2015The monitoring of the plasmatic concentrations of cardiovascular drugs is crucial for understanding their pharmacokinetics and pharmacodynamics. A simple, sensitive,...
Simultaneous Determination and Pharmacokinetic Study of Losartan, Losartan Carboxylic Acid, Ramipril, Ramiprilat, and Hydrochlorothiazide in Rat Plasma by a Liquid Chromatography/Tandem Mass Spectrometry Method.
The monitoring of the plasmatic concentrations of cardiovascular drugs is crucial for understanding their pharmacokinetics and pharmacodynamics. A simple, sensitive, specific, and high-throughput liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous estimation and pharmacokinetic study of losartan (LOS), losartan carboxylic acid (LCA), ramipril (RAM), ramiprilate (RPT), and hydrochlorothiazide (HCZ) in rat plasma using irbesartan (IBS) and metolazone (MET) as internal standards (ISs). After solid phase extraction (SPE), analytes and ISs were separated on an Agilent Poroshell 120, EC-C18 (50 mm × 4.6 mm, i.d., 2.7 μm) column with a mobile phase consisting of methanol/water (85:15, v/v) containing 5 mmol/L ammonium formate and 0.1% formic acid at a flow rate of 0.4 mL/min. The precursor → product ion transitions for the analytes and ISs were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring (MRM) mode and switching the electrospray ionization (ESI) mode during chromatography from positive (to detect LOS, LCA, RAM, RPT, and IBS) to negative (to detect HCZ and MET). The method was validated as per the FDA guidelines and it exhibited sufficient specificity, accuracy, and precision. The method was found to be linear in the range of 3-3000 ng/mL for LOS and LCA, 0.1-200 ng/mL for RAM and RPT, and 1-1500 ng/mL for HCZ. The described method was successfully applied to the preclinical pharmacokinetic study of analytes after oral administration of a mixture of LOS (10 mg/kg), RAM (1 mg/kg), and HCZ (2.5 mg/kg) in rats.
PubMed: 26839805
DOI: 10.3797/scipharm.1410-15 -
British Journal of Clinical Pharmacology May 1983The plasma potassium responses to 1 week's treatment with metolazone 0.625 mg, 1.25 mg and 2.5 mg in combination with spironolactone 50 mg, and metolazone 2.5 alone were... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
The plasma potassium responses to 1 week's treatment with metolazone 0.625 mg, 1.25 mg and 2.5 mg in combination with spironolactone 50 mg, and metolazone 2.5 alone were examined in a double-blind, crossover study in twelve healthy subjects. Spironolactone attenuated the hypokalaemia induced by metolazone--addition of spironolactone 50 mg to metolazone 2.5 mg raised plasma potassium by 0.18 mmol/l (P less than 0.025). In the presence of spironolactone, a linear log metolazone dose-plasma potassium response relationship (P less than 0.01) was demonstrated. Spironolactone was unable to compensate fully for metolazone's hypokalaemic effect although in combination with metolazone 0.625 mg and 1.25 mg, plasma potassium concentration was maintained close to pretreatment levels. The human bioassay employed provided conveniently quantitative information which allows the rational development of a fixed dose diuretic-spironolactone combination tablet.
Topics: Adult; Diuretics; Double-Blind Method; Drug Combinations; Humans; Male; Metolazone; Potassium; Spironolactone
PubMed: 6860532
DOI: 10.1111/j.1365-2125.1983.tb02092.x -
Molecules (Basel, Switzerland) Jan 2023Sodium (S)-2-(dithiocarboxylato((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)amino)-4(methylthio)butanoate (GMDTC) is the first compound to use cadmium repellent as an...
Sodium (S)-2-(dithiocarboxylato((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)amino)-4(methylthio)butanoate (GMDTC) is the first compound to use cadmium repellent as an indication. In this paper, we established and validated a bioanalytical method for the determination of GMDTC in rat plasma, and used it to determine the drug concentrations in the plasma of rats after intravenous dosing in different genders and dosages. After pretreating the plasma samples with an acetonitrile-water-ammonia solution (70:30:1.25, //), liquid chromatographic separations were efficiently achieved with a XBridge C18 column using a 5 min gradient system of aqueous ammonium bicarbonate and 95% acetonitrile-water solution (95:5, /) as the eluent. The GMDTC and metolazone (internal standard, IS) detection were carried out using high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (LC-MS/MS), monitored at / 390.06-324.1 (for the GMDTC, tR: 2.03 min) and / 366.0-259.2 (for IS, tR: 3.88 min). The GMDTC was stable under various testing conditions, and this analytical method conforms to the verification standard of biological analysis methods. The half-life (t) was determined to be 0.54-0.65 h for the intravenous, mean distribution volume and clearances were 1.08-2.08 L/kg and 1-3 L/h/kg, respectively. The AUC and AUC found after increasing the dosage exhibited a linear relationship with the administered dose. There were no statistically significant differences in the values obtained for the different genders at dosages of 50, 100 and 250 mg/kg, respectively ( > 0.05). This is the first report of a bioanalytical method to quantify GMDTC in rat plasma using LC-MS/MS, which provides useful information for the study of its pharmacological effects and clinical applications.
Topics: Rats; Female; Male; Animals; Chromatography, Liquid; Tandem Mass Spectrometry; Chromatography, High Pressure Liquid; Indicators and Reagents; Cadmium; Reproducibility of Results
PubMed: 36770860
DOI: 10.3390/molecules28031191 -
Cureus Apr 2020Hyponatraemia is the most common electrolyte imbalance found in hospital population and worldwide thiazide and loop-diuretics are among the most widely used drugs....
Hyponatraemia is the most common electrolyte imbalance found in hospital population and worldwide thiazide and loop-diuretics are among the most widely used drugs. Syndrome of inappropriate antidiuresis diagnosis (SIAD) is complicated in the presence of diuretic therapy due to the misleading clinical assessment of the extracellular volume status, and in order to make SIAD diagnosis it is often necessary to withdraw diuretic therapy. Our study aimed to investigate the diagnostic role of these alternative markers of volume status, serum uric acid (sUA) and fractional excretion of uric acid (FEUA), in hyponatraemic patients treated with different diuretic drugs. Eighty-nine patients were enrolled with the diagnosis of SIAD, diuretic-induced hyponatremia (DIH, treated with furosemide and potassium canrenoate) or thiazide-induced hyponatremia (TIH, treated with hydrochlorothiazide, metolazone or indapamide) and investigated with receiver operating characteristic analysis and a sensitivity test. Our results show that FEUA discriminated better than sUA between SIAD and DIH patients (area under curve 0.96, <0.001 vs. 0.88, <0.001) while it was a poor marker to discriminate between SIAD and TIH (0.65, NS vs. 0.67, NS). In conclusions, FEUA is an excellent marker to discriminate SIAD vs. sodium depleted patients treated with furosemide and/or potassium canrenoate while the diuretic withdrawal, beyond obtaining a serum Na normalization, is still mandatory for differential diagnosis of sodium depleted patients affected by thiazide-induced hyponatraemia.
PubMed: 32455079
DOI: 10.7759/cureus.7762 -
The Journal of Biological Chemistry Mar 2002The bumetanide-sensitive Na(+):K(+):2Cl(-) cotransporter (BSC1) is the major pathway for salt reabsorption in the apical membrane of the mammalian thick ascending limb...
The bumetanide-sensitive Na(+):K(+):2Cl(-) cotransporter (BSC1) is the major pathway for salt reabsorption in the apical membrane of the mammalian thick ascending limb of Henle. Three isoforms of the cotransporter, known as A, B, and F, exhibit axial expression along the thick ascending limb. We report here a functional comparison of the three isoforms from mouse kidney. When expressed in Xenopus oocytes the mBSC1-A isoform showed higher capacity of transport, with no difference in the amount of surface expression. Kinetic characterization revealed divergent affinities for the three cotransported ions. The observed EC(50) values for Na(+), K(+), and Cl(-) were 5.0 +/- 3.9, 0.96 +/- 0.16, and 22.2 +/- 4.8 mm for mBSC1-A; 3.0 +/- 0.6, 0.76 +/- 0.07, and 11.6 +/- 0.7 mm for mBSC1-B; and 20.6 +/- 7.2, 1.54 +/- 0.16, and 29.2 +/- 2.1 mm for mBSC1-F, respectively. Bumetanide sensitivity was higher in mBSC1-B compared with the mBSC1-A and mBSC1-F isoforms. All three transporters were partially inhibited by hypotonicity but to different extents. The cell swelling-induced inhibition profile was mBSC1-F > mBSC1-B > mBSC1-A. The function of the Na(+):K(+):2Cl(-) cotransporter was not affected by extracellular pH or by the addition of metolazone, 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), or R(+)-[(2-n-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1-H-indenyl-5-yl)-oxy]acetic acid (DIOA) to the extracellular medium. In contrast, exposure of oocytes to HgCl(2) before the uptake period reduced the activity of the cotransporter. The effect of HgCl(2) was dose-dependent, and mBSC1-A and mBSC1-B exhibited higher affinity than mBSC1-F. Overall, the functional comparison of the murine apical renal-specific Na(+):K(+):2Cl(-) cotransporter isoforms A, B, and F reveals important functional, pharmacological, and kinetic differences, with both physiological and structural implications.
Topics: Amino Acid Sequence; Animals; Bumetanide; Female; Hydrogen-Ion Concentration; Molecular Sequence Data; Osmolar Concentration; Protein Isoforms; Sodium Potassium Chloride Symporter Inhibitors; Sodium-Potassium-Chloride Symporters; Xenopus laevis
PubMed: 11790783
DOI: 10.1074/jbc.M110442200 -
European Review For Medical and... Apr 2021Up to 50% of patients hospitalized for acute heart failure (AHF) show resistance to diuretics. This condition contributes to a prolonged hospital length of stay and a... (Comparative Study)
Comparative Study Meta-Analysis
OBJECTIVE
Up to 50% of patients hospitalized for acute heart failure (AHF) show resistance to diuretics. This condition contributes to a prolonged hospital length of stay and a higher risk of death. This review aimed to investigate whether a diuretic therapeutic approach more effective than furosemide alone exists for patients with diuretic-resistant AHF.
MATERIALS AND METHODS
We identified all randomized controlled trials (RCTs) evaluating diuretic therapy in patients with diuretic-resistant AHF. We searched Pubmed, BioMed Central, and Cochrane CENTRAL databases.
RESULTS
Six RCTs were identified, involving a total of 845 patients. The P-score ranges from 0.6663 for furosemide to 0.2294 for the tolvaptan-furosemide. We found no significant differences in efficacy for any drug comparison.
CONCLUSIONS
None of the diuretics considered in RCTs performed to date (tolvaptan, metolazone, hydrochlorothiazide, indapamide) appear to be more effective than furosemide therapy alone for the treatment of patients with diuretic-resistant AHF.
Topics: Acute Disease; Carbonic Anhydrase Inhibitors; Diuretics; Drug Resistance; Heart Failure; Humans; Randomized Controlled Trials as Topic
PubMed: 33877660
DOI: 10.26355/eurrev_202104_25550