Kinetics of polythiazide

Hobbs, Donald C.; Twomey, Thomas M.

doi:10.1002/cpt1978232241

Cited by 21 publications

(2 citation statements)

References 3 publications

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“…There are no data available which concern metabolism of the drug (Hobbs and Twomey, 1978). (table V) Chlorthalidone is a diuretic with pharmacological effects similar to thiazides, although it differs chemically from that group ( fig.…”

Section: Plasma Kinetics and Eliminationmentioning

confidence: 98%

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Clinical Pharmacokinetics of Diuretics

Beermann¹,

Groschinsky-Grind²

1980

Clinical Pharmacokinetics

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Despite extensive use of diuretics, for only a few have their pharmacokinetics been evaluated.Bendroflumethiazide is completely absorbed and uptake from the gastrointestinal tract is not changed by food. Plasma half-life is about 3h. Apparent volume of distribution averages 1.5£/kg. Up to 'two thirds of the drug is eliminated via non-renal routes. " Hydrochlorothiazide is 65 % absorbed in healthy fasting subjects and 75 % absorbed when given with food. The increased uptake appears to be caused by decreased gastric emptying rate. Absorption is impaired in patients who have undergone intestinal shunt surgery and in some patients with cardiac failure. Plasma half-life averages 10h in subjects with normal renal function. It is prolonged in renal failure as the drug is mainly eliminated via the kidneys in unchanged form. ' " The bioavailability of hydroflumethiazide is at least 50 %. Elimination hal/-life is about 17h in normal subjects and IOh in patients with cardiac failure. The drug is largely eliminated unchanged, in the urine. The half-life of poly thiazide is approximately 26h. About 20 % of an oral dose is cleared via the kidneys. Chlorthalidone is 65 % absorbed. Up to 75 % of a dose is bound to'plasmaproteins and extensively to blood cells. Only 1.4 % of the tota'i amount of the drug in blood is found in plasma.' Plasma half-life averages 40 to 65h. Apparent volume of distribution is close to 300£. This diuretic is mainly eliminated in the urine, although it is metabolised to some extent. Bumetanide is completely absorbed. Up to 96 % is bound to plasma proteins. Apparent volume of distribution ranges from 12 to 35£. Plasma hal/-life is 1.2 to J .5h in healthy subjects and does not appear to be prolonged in renal failure. Renal and non-renal clearance contributes equalfY to its elimination. The uptake of frusemide (furosemide) from the gastrointestinal tract is :about 65 % and is decreased in uraemia and nephrosis. Protein binding is 96 to 98 % and is, diminished in nephrosis. Plasma half-life is approximately 50 minutes in healthy subjects and is prolonged about 3 times in renalfailure. Apparent volumeo/distribution (Vd~rangesfrqm J4 to 11£. Urinary excretion and non-renal elimination contribute almost equally to plasma clearance. The uptake of/ §...mi/ori~is at least 50 % and is diminished when given with food. Plasma half-life averages IOh. Amiloride is essentially eliminated unchanged in'the urine. '

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Section: Plasma Kinetics and Eliminationmentioning

confidence: 98%

“…(ml/h/kg) ~ phase 16.6 ± 6 e 0.32-0.34 SFM, SFD (n=2) 9.6± 2.8 e 0.21 ±0.07 e A sensitive GLC assay of polythiazide has been described by Hobbs and Twomey (1978).…”

Section: Renal Clearance Assaybmentioning

confidence: 99%

Clinical Pharmacokinetics of Diuretics

Beermann¹,

Groschinsky-Grind²

1980

Clinical Pharmacokinetics

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HPLC determination of benzthiazide in biologic material

Meyer¹,

Hwang²,

Straughn³

et al. 1982

Biopharm & Drug Disp

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An assay was developed for benzthiazide in plasma, urine and feces, using high performance liquid chromatography (HPLC). A reverse-phase column was employed, with quantitation af 280 nm, using polythiazide as an internal standard. In three of four human subjects who received a 50 mg benzthiazide tablet the plasma concentrations were below the 10 ng ml-1 sensitivity limit of the assay, and the urinary recovery averaged less than one per cent of the dose. One subject received a 50 mg dose as both a tablet and a solution; the urinary recoveries for these two doses were 1.7 and 10.4 per cent, respectively. Fecal samples, obtained from two subjects who received 50 mg tablets, were estimated to contain approximately 80 per cent of the administered dose.

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Bioavailability of bemetizide and triamterene from a combination formulation

Brodie¹,

Chasseaud²,

Darragh

et al. 1982

Biopharm & Drug Disp

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The bioavailability of the thiazide diuretic bemetizide from a tablet containing 25 mg of this drug and 50 mg of the chemically unrelated diuretic triamterene was lower than, and significantly different (p less than 0.01) from that from a tablet containing 25 mg bemetizide alone. The mean peak plasma level of bemetizide after administration of the combination tablet (68.3 ng ml-1) was lower than that after administration of bemetizide alone (87.9 ng ml-1), although the times of occurrence of the peak levels were similar. The bioavailability of triamterene from the combination tablet was greater than, but not significantly different from that after administration of a capsule containing 50 mg triamterene alone. The mean peak plasma level of triamterene after administration of the combination tablet (44.6 ng ml-1) was higher than and significantly different (p less than 0.001) from that after administration of triamterene alone (15.7 ng ml-1). Although bemetizide is unstable in urine, measurement of the apparent excretion of unchanged drug in the 24 h post-dose urine (less than 4 per cent of the dose) agreed with the estimate of drug bioavailability from the plasma level data. Less than 2 per cent of the dose of triamterene was excreted unchanged in the 24 h post-dose urine, but the urinary excretion data also agreed with the bioavailability estimates from the plasma level data. The results of this study and those reported in the literature suggest that because of their physicochemical properties, the bioavailability of some thiazides and triamterene needs to be evaluated when new formulations of these drugs are produced. However, with respect to the combination formulation reported in this paper, the difference in bioavailability of the thiazide component did not detectably effect the diuretic activity of the formulation.

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Kinetics of polythiazide

Cited by 21 publications

References 3 publications

Clinical Pharmacokinetics of Diuretics

Clinical Pharmacokinetics of Diuretics

HPLC determination of benzthiazide in biologic material

Bioavailability of bemetizide and triamterene from a combination formulation

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