Effects of antihypertensive drugs on SBP variability are dose-dependent and persist when used in combinations .
Use of a high dose of a calcium channel blocker alone or in combination with other agents is therefore likely to be particularly effective in prevention of stroke
BACKGROUND AND PURPOSE Recent studies have shown that visit-to-visit blood pressure variability is a powerful risk factor for stroke , is reduced by calcium channel blockers and diuretics , and increased by β-blockers .
However , it is unknown whether these effects are dose-dependent and persist in combination with other drugs .
The case for low dose diuretics in hypertension: comparison of low and conventional doses of cyclopenthiazide.
In a double blind placebo controlled r and omised parallel study the antihypertensive activity and adverse biochemical effects of three doses of cyclopenthiazide were evaluated in patients with mild essential hypertension that had been recently diagnosed or was being treated with a single drug . After a four week placebo washout period 53 patients with diastolic blood pressures between 90 - 110 mm Hg were r and omly assigned to 50 , 125 , or 500 micrograms cyclopenthiazide or matching placebo for an eight week period of treatment . Blood pressure was measured in the patients ' homes by the same observer every two weeks . Serum urea , electrolytes , urate , and creatinine concentrations and 24 hour urinary sodium excretion were monitored every four weeks and serum magnesium concentration and plasma renin activity at the end of the washout and treatment periods . After eight weeks of treatment systolic and diastolic blood pressures were significantly reduced in patients taking 125 and 500 micrograms cyclopenthiazide when compared with those taking placebo . The decrement in serum potassium concentration ( 0.6 mmol/l ) and increase in serum urate concentration 0.06 mmol/l ) were greatest with the 500 micrograms dose , the increase in serum urate concentration alone being significant . No change in serum magnesium concentration or 24 hour urinary sodium excretion was noted with any dose of cyclopenthiazide . Only the 500 micrograms dose of cyclopenthiazide significantly increased the mean plasma renin activity ( 1.8 ( 95 % confidence interval 0.2 to 3.4)-5.4 ( 3.9 to 6.8 ) nmol angiotensin I/l/h ) ; the other doses like the placebo had no effect . Cyclopenthiazide 125 micrograms , a dose lower than is currently marketed , produced a similar hypotensive response to 500 micrograms of the drug without up setting the biochemical profile
Effects of antihypertensive drugs on SBP variability are dose-dependent and persist when used in combinations .
Use of a high dose of a calcium channel blocker alone or in combination with other agents is therefore likely to be particularly effective in prevention of stroke
BACKGROUND AND PURPOSE Recent studies have shown that visit-to-visit blood pressure variability is a powerful risk factor for stroke , is reduced by calcium channel blockers and diuretics , and increased by β-blockers .
However , it is unknown whether these effects are dose-dependent and persist in combination with other drugs .