Diuretics triamterene

Potassium Sparing Diuretics. Triamterene and amiloride, potassium sparing diuretics, by themselves produce only slight antihypertensive effects. The main use is to prevent or to treat the hypokalemia induced by thiazide-type and high ceiling loop diuretics, such as furosemide and bumetanide. 

The sulfonamide diuretics cause problems through excessive excretion of potassium which diffuses into the urine as Na+ is removed in the distal tubule. This cation exchange is prevented by a different type of diuretic, triamterene (198), which was developed by following the observation that xanthopterin (199) affects renal function. The pyrazine amiloride (200) also increases Na+ output and spares K+, and is used in conjunction with chlorothiazide. It has been shown to reduce the electrical potential gradient along which K+ migrates into the lumen of the tubule. 

Potassium-rich foods (e.g. bananas) can cause hyperkalaemia if the medication(s) used also tend to cause hyperkalaemia, for example potassiumsparing diuretics (triamterene, spironolactone), ACE inhibitors (captopril, enalapril, etc,), angiotensin receptor blockers and indometacin,... 

Like other diuretics, triamterene occasionally causes interstitial nephritis (4), but it has also been responsible for other renal problems, notably reversible non-oliguric renal insufficiency when it is given along with indometa-cin (or presumably any other inhibitor of prostaglandin synthesis) (5). 

Barroso, M.B. Alonso, R.M. Jimenez, R.M. Simultaneous determination of the diuretics triamterene and furosemide in pharmaceutical formulations and urine by HPLC-EC. J.Liq.Chrom.Rel.Technol.,... 

Swart, K.J. Botha, H. Rapid method for the determination of the diuretic triamterene and its metabolites in plasma and urine by high-performance liquid chromatography. J.Chromatogr., 1987, 413, 315-319... 

Brodie, R.R. Chasseaud, L.F. Taylor, T. Walmseley, L.M. Determination of the diuretic triamterene in the plasma and urine of humans by high-performance liquid chromatography. J.Chromatogr., 1979, 164, 527-533... 

Vargas, F. and Fuentes, A., Evidence of formation and participation of singlet oxygen in the in vitro phototoxicity of the combined diuretic triamterene and hydrochlorothiazide. Die Pharmazie, 52, 328, 1997. 

For the much-used pteridine diuretic triamterene, 2,4,7-triamino-6-phenylpteridine, see Section 14. i. For further reading on the biochemistry of anti-folic agents, see Blakley (1969). 

Modern diuretics contain no mercury. Many of them, like amiloride (N-amidino-3,5 diamino-6-chloropyrazine-2-carboxamide) and the pteri-dine diuretic, triamterene ( Dytac ) (r. i), act on the membrane lining the distal tubule, preventing resorption of sodium ions (and hence of water) (Crabbe, 1968 Wiebelhaus et al. 1965). The simpler molecule 2,4-diamino-6,7-dimethylpteridine is almost as active. Others, like frus-emide and ethacrynic acid, seem to act somewhat similarly. It is less certain that the thiazides, such as (14.2), act in this way. For more information on the action of diuretics, see Suki, Eknoyan, and Martinez-Maldonado... 

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