Differences in antihypertensive effect were due to potency rather than efficacy .
This synthesis accomplishes for PSDs what has already been achieved for thiazide-type diuretics and other antihypertensives and can guide the application of these underutilized medicines
BACKGROUND Potassium-sparing diuretics ( PSDs ) are valuable antihypertensives with additional benefits unrelated to control of systolic blood pressure ( SBP ) .
However , their key parameters affecting SBP and serum potassium are poorly defined , fostering underutilization .
Blood pressure lowering and potassium conservation by triamterene‐hydrochlorothiazide and amiloride‐hydrochlorothiazide in hypertension
Effects of once‐daily doses of 50 mg triamterene with 25 mg hydrochlorothiazide and 5 mg amiloride with 50 mg hydrochlorothiazide were compared in a r and omized , multicenter study of 84 adult subjects with mild to moderate hypertension ( diastolic blood pressure 90 to 114 mm Hg ) . After a 3‐wk placebo lead‐in period , the subjects entered a 6‐wk treatment period . The two drug regimens were compared with respect to antihypertensive effects and effects on serum potassium and magnesium levels during the final week of drug therapy , with the use of the last week of placebo therapy as a covariate . Both drug regimens substantially reduced mean supine systolic and diastolic blood pressures to well within normal limits ; there was no significant difference between the two groups . Twenty‐four of the 41 subjects receiving triamterene‐hydrochlorothiazide ( 59 % ) and 29 of the 43 patients receiving amiloride‐hydrochlorothiazide ( 67 % ) had diastolic blood pressure < 90 mm Hg at week 9 . Five subjects receiving amiloride‐hydrochlorothiazide ( 12 % ) and two subjects receiving triamterene‐hydrochlorothiazide ( 5 % ) had hypokalemia ( serum potassium level < 3.5 mEq/l ) at week 9 . The average decrease in serum potassium levels  during amiloride‐hydrochlorothiazide therapy ( −0.33 ± 0.08 mEq/l ) was greater than that after triamterene‐hydrochlorothiazide ( −0.08 ± 0.07 mEq/l ) . Serum magnesium levels were not changed by either regimen . Weight loss was greater in the amiloride‐hydrochlorothiazide group than in the triamterene‐hydrochlorothiazide group . It is reasonable to assume that the greater potassium loss during amiloride‐hydrochlorothiazide therapy than during triamterene‐hydrochlorothiazide therapy was a consequence of the larger dose of hydrochlorothiazide in the former ( 50 mg ) compared with the latter ( 25 mg ) . Although the effect on lowering blood pressure by amiloride‐hydrochlorothiazide was slightly greater than that by triamterene‐hydrochlorothiazide ( also consistent with the larger dose of hydrochlorothiazide ) , the difference was small and not significant . Triamterene‐hydrochlorothiazide at low doses is effective in the treatment of hypertension
Differences in antihypertensive effect were due to potency rather than efficacy .
This synthesis accomplishes for PSDs what has already been achieved for thiazide-type diuretics and other antihypertensives and can guide the application of these underutilized medicines
BACKGROUND Potassium-sparing diuretics ( PSDs ) are valuable antihypertensives with additional benefits unrelated to control of systolic blood pressure ( SBP ) .
However , their key parameters affecting SBP and serum potassium are poorly defined , fostering underutilization .