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Effects of an acebutolol-hydrochlorothiazide combination on urinary solute excretion in healthy adults.

Leary WP, Reyes AJ, van der Byl K.

Ten healthy adult male volunteers were studied to assess the urinary effects of a single dose of a combination of hydrochlorothiazide 12.5 mg and acebutolol 200 mg (HZAL). The formation induced a significant increase in the 24-hour urinary output of sodium. Outputs of fluid, chloride, potassium, calcium, magnesium, zinc, total inorganic phosphate and creatinine were unaffected. With the exception of Mg2+ flow, times to maximal urinary flows of fluid and solutes were shortened by HZAL. These qualitative changes resemble those induced by hydrochlorothiazide but did not achieve quantitative significance, either because the constituent diuretic dose was too small or because acebutolol compensated for some of its effects.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3941959&dopt=Abstract hydrochlorothiazide Microzide



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Effect of cilazapril with or without low dose thiazide on LDL peroxidation in [correction of peroxidationin] hypertensive patients.

Hussein O, Radan A, Reuven V.

Lipid Research Laboratory, Internal Medicine Department A, Sieff Government Hospital, PO Box 1008, Safed 13100, Israel. husseinosamah newmail.net

BACKGROUND: This study aims to address the question, "Does equivalent blood pressure (BP) reduction by cilazapril alone or in combination with low dose of both cilazapril and hydrochlorothiazide have an equal effect on lowering oxidation of plasma LDL?" METHODS: Fifteen patients with untreated arterial hypertension were enrolled. Patients received 5 mg/d cilazapril (C5) for 6 weeks and were treated with a combination of 2.5 mg/d cilazapril and 12.5 mg/d hydrochlorothiazide (C2.5,HCTz) for an additional 2 months to achieve the same BP reduction as in the initial period. Treatment with a combination of 5 mg/d cilazapril and 12.5 mg/d hydrochlorothiazide (C5,HCTz) was administered for an additional 6 weeks. RESULTS: Treatment with C5 or in combination with C2.5,HCTz lowered systolic BP by the same magnitude (P <.05). Treatment with C5,HCTz decreased systolic BP an additional 7% and diastolic BP by 6% (P <.05). The LDL of 15 hypertensive patients demonstrated a 16.7% shorter lag time to initiation of peroxidation and 8.5% higher malonyldialdehyde levels at point of maximal peroxidation than LDL from 10 healthy controls (P <.05). Treatment with C5 decreased LDL tendency to peroxidation (lag time was prolonged by 43%, P <.05; malonyldialdehyde levels decreased by 8.3%). The combined treatment of C2.5,HCTz achieved the same BP reduction, but did not increase LDL resistance to peroxidation. Treatment with C5,HCTz achieved the same reduction in malonyldialdehyde levels in LDL than C5 therapy, but prolonged lag time by 17% (P <.05). CONCLUSIONS: The decreased tendency of LDL to peroxidation in hypertensive patients treated by cilazapril is due to the inherent effect of cilazapril, and not to a reduction in BP.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12944031&dopt=Abstract hydrochlorothiazide Microzide



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Colorimetric analysis of some diuretic drugs: hydrochlorothiazide and spironolactone.

Moussa BA, el Kousy NM.

Two convenient spectrophotometric methods were developed for the determination of hydrochlorothiazide and spironolactone. A specific colour reaction for the determination of hydrochlorothiazide is reported. One method is based on the reaction of hydrochlorothiazide with n-butylamine and cobaltous chloride in anhydrous methanol. A blue-violet colour is produced and is measured at 570 nm. A highly selective colorimetric method was adopted for the analysis of spironolactone by reacting with isoniazid forming a coloured hydrazone derivative and subsequent measurement of the coloured product at 405 nm.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=4000904&dopt=Abstract hydrochlorothiazide Microzide



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Three new spectrophotometric methods applied to the simultaneous determination of hydrochlorothiazide and irbesartan.

Erk N.

Department of Analytical Chemistry, Faculty of Pharmacy, University of Ankara, Turkey. erk pharmacy.ankara.edu.tr

This work involves the simultaneous determination of hydrochlorothiazide and irbesartan in a binary mixture without previous separation by three new analytical methods. The first method, based on compensation technique, is presented for the derivative spectrophotometric determination of binary mixtures with overlapping spectra. By using ratios of the derivative maxima or the derivative minimum, the exact contribution of either component in the binary mixture can be measured and the amounts quantified. The second method uses of the first derivative of the ratio spectra. The ratio spectra were obtained by dividing the absorption spectra of the binary mixture by that of one of the components. The amplitudes in the first derivative of the ratio spectra at 231, 266, 279, 238 and 248 nm were selected to determine hydrochlorothiazide and irbesartan in binary mixtures. The concentration of the other components are then determined from their respective calibration graphs treated similarly. With the third method, the absorbance ratio method, the determination of hydrochlorothiazide and irbesartan was performed using the absorbances read at 272 nm, 241 nm and 263 nm in the zero-order spectra of their mixture. The absorbance ratio was also developed as a comparison method. The three methods are simple, accurate, rapid and require no preliminary separation steps and can, therefore, be used for routine analysis of both drugs in quality control laboratories.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12967029&dopt=Abstract hydrochlorothiazide Microzide



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[Regression of left heart hypertrophy in arterial hypertension: principles, experimental and clinical findings]

[Article in German]

Klaus D.

Left ventricular hypertrophy is the consequence of a structural adaptation of the heart in response to the chronic pressure load, leading to a reduction of the increased systolic wall stress. Studies in spontaneously hypertensive rats have shown, that left ventricular hypertrophy can be influenced by various, but not all antihypertensive agents. Alpha-methyldopa, captopril, beta-blockers and calcium channel blockers resulted in reversal of hypertrophy. Treatment with diuretics, hydralazine or minoxidil did not increase or alter degree of myocardial hypertrophy despite normalization of blood pressure. The biochemical profile after reversal of hypertrophy differs according to antihypertensive therapy, i.e. alpha-methyldopa induces an increase in collagen content, whereas captopril does not alter the collagen content of the myocardium. Adrenergic factors play an important role in modulating the response of the heart. In clinical studies the reduction in cardiac mass does not depend solely on the antihypertensive effect on blood pressure levels. There is only a weak correlation between decrease of left ventricular hypertrophy and fall of blood pressure level, as is shown in 12 patients with essential hypertension, treated with captopril over 6 months. The degree of regression of hypertrophy is influenced by stability of blood pressure control (diurnal variations and response to stress are more important than single casual values), neurohumoral response, presence of associated cardiac diseases, cause and severity of hypertension, genetic factors and age. We studied the regression of left ventricular hypertrophy by M-mode-echocardiography in 12 patients with mild or moderate essential hypertension during a 6-month therapy with captopril (50-75 mg p.d.) and hydrochlorothiazide (50 mg p.d.). In 11 of 12 patients captopril treatment resulted in a reduction of LV-mass of 30.9 +/- 15.1% and wall thickness. Peak systolic and endsystolic wall stress decreased significantly (-29.1% and -27.2%, resp.) after blood pressure reduction, but were still slightly elevated. Ejection fraction increased by 5.4% (p less than or equal to 0.05). 6 hypertensive patients treated for 6 months with metoprolol (150 mg p.d.) and hydrochlorothiazide (50 mg p.d.) do not show significant reduction of LV-mass (-6.5%). Peak and endsystolic wall stress were significantly reduced (-33.1% and -11.5%, resp.) as in captopril therapy. In 34 patients with severe hypertension treated with captopril, hydrochlorothiazide and metoprolol over 30 months, we observed a decline in the Sokolow-Lyon-Index from 4.8 +/- 1.1 mV to 3.8 +/- 0.5 mV after 6 months.(ABSTRACT TRUNCATED AT 400 WORDS)

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2936016&dopt=Abstract hydrochlorothiazide Microzide