Microzide
[On the bioavailability of hydrochlorothiazide and triamterene from commercial drugs (author's transl)]

[Article in German]

Knauf H, Mohrke W, Mutschler E, Volger KD.

In a study on the bioavailability of triamterene and hydrochlorothiazide from 3 diuretics, preparation A (25 mg hydrochlorothiazide), preparation B (50 mg triamterene) and preparation C (combination of hydrochlorothiazide and triamterene), the data for tmax, Cmax, AUC and the cumulative urine excretion were determined in 7 healthy volunteers. The different formulations of the diuretics influenced the kinetics of the agents. The in vivo data agreed well with those obtained in vitro. Plasma levels of triamterene and its active metabolite from preparation C were reached more rapidly than from preparation B. However, the bioavailability of the agents was not significant different in the two diuretics when given immediately after breakfast. The AUC-data of hydrochlorothiazide determined after administration of preparation A or C do not differ significantly, only the comulative excretion of hydrochlorothiazide in urine is greater after application of preparation A than after application of preparation C.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7191258&dopt=Abstract hydrochlorothiazide Microzide



Microzide
24-hour urine composition of Sri Lankan adults and their response to 100 mg dihydrochlorothiazide.

Vinayagamoorthy T.

In the present study, 205 'normal hospitalised subjects' in the age group 16-60 years were included in a clinical trial to estimate the 24-hour urinary composition. Their response to 100 mg dihydrochlorothiazide was also determined. The study revealed that there is a marked difference in the 24-hour urine volume and composition between that observed in the present study and that presented in the modern literature; 100 mg dihydrochlorothiazide was found to produce a significant diuretic and natriuretic effect in normal Sri Lankan adults. There is a very high correlation between the volume of urine and the cations in the basal excretion as well as with the standard diuretic. The coefficient of regression of volume on cations in the basal excretion was found to be less than that with the standard diuretic.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7191688&dopt=Abstract hydrochlorothiazide Microzide



Microzide
Stability-indicating assay for hydrochlorothiazide.

Daniels SL, Vanderwielen AJ.

A stability-indicating method for determining hydrochlorothiazide in tablet formulations and in the bulk form is described. Hydrochlorothiazide is dissolved or extracted using methanol. An aliquot of the solution, containing sulfadiazine as an internal standard, is chromatographed on a 10 micron C18 column with an aqueous mobile phase containing 5% methanol as the modifier. The pH is adjusted to about 4.5 with acetic acid. The method gave accurate results for nine lots (four different suppliers) of tablets and two bulk drug lots (two different suppliers). The assay has a relative standard deviation of about 1%. The method can also be used as a test for impurities in hydrochlorothiazide. The data in this study indicate that the test should give accurate results for impurities between 0.1 and 5%.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7205229&dopt=Abstract hydrochlorothiazide Microzide



Microzide
Inability of indomethacin to modify hydrochlorothiazide diuresis and natriuresis by the chimpanzee kidney.

Fanelli GM Jr, Bohn DL, Camp AE, Shum WK.

A drug interaction study in the chimpanzee by using indomethacin and hydrochlorothiazide has shown conclusively that the diuretic and saluretic properties of hydrochlorothiazide were not compromised by indomethacin. This was true whether hydrochlorothiazide or indomethacin was administered first. The renal clearance of hydrochlorothiazide was not influenced by indomethacin nor was the renal clearance of indomethacin significantly altered by hydrochlorothiazide. Indomethacin alone caused a small but significant increase in sodium, potassium and chloride excretion and in Curate/glomerular filtration rate. In control experiments with placebo, potassium excretion was also significantly increased. The implications of these observations remain obscure. In all experiments utilizing hydrochlorothiazide, the well known renal effects of this agent were clearly evident under these experimental conditions.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7205619&dopt=Abstract hydrochlorothiazide Microzide



Microzide
Effects of diuretics on urate and calcium excretion.

Yu T, Berger L, Sarkozi L, Kaung C.

Forty-nine patients with gout, many with hypertension and/or renal calculi, were given hydrochlorothiazide, furosemide, or ticrynafen. Diuresis and increased clearances of sodium (Na), potassium (K), chloride (Cl), and calcium (Ca) occurred after a single dose of hydrochlorothiazide, 100 mg, or furosemide, 40 mg, orally. There was very slight change in urate and phosphorus clearances. With prolonged use of hydrochloride or furosemide, diuresis and increased electrolyte excretion disappeared. Urate and Ca excretion fell with hydrochlorothiazide. With long-term use of furosemide, urate excretion was suppressed, but Ca excretion was sustained. Ticrynafen produced diuresis and increased clearances of Na, K, and Cl. Calcium excretion was increased after a single dose and minimally decreased after long-term use. Most striking was the severe and rather sustained uricosuria. Though ticrynafen is an effective uricosuric, natriuretic, and antihypertensive agent, its hepatotoxicity and nephrotoxicity mitigate against its clinical use.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7235811&dopt=Abstract hydrochlorothiazide Microzide