Single-agent and combination therapy of essential hypertension

Controlling Blood Pressure in 50% of All Hypertensive Patients: An Achievable Goal in the Healthy People 2010 Report?

Background

One important objective defined in the Healthy People 2010 report was to improve blood pressure (BP) control to < 140/90 mm Hg in 50% of all hypertensive patients. Because the US population is becoming older, more obese, and ethnically diverse, the health and economic benefits of reaching this goal become more valuable each year. Hypertension control rates are currently at ∼ 31% of all hypertensives and have risen slowly and erratically since 1988. In the absence of a coordinated strategic plan, achieving this critically important goal for BP control is highly unlikely.

Methods

A selected literature review was undertaken to briefly assess the cardiovascular benefits of controlling hypertension. Greater focus was placed on variables that impact hypertension awareness, treatment, and control. The impact on hypertension control rates of theoretic changes in awareness, treatment, and control individually and collectively was examined. Four categories of potential barriers to optimizing BP control are discussed: systems, provider, patient, and treatment factors.

Results

Raising awareness to 80% of all hypertensives, ensuring treatment of 90% of aware hypertensives, and controlling BP to < 140/90 mm Hg in 70% of treated patients would achieve control rates of 50%.

Conclusions

The barriers to achieving the Healthy People 2010 goal of controlling hypertension in 50% of all patients are formidable but appear to be resolvable with a coordinated strategic plan. Given projected demographic changes in the United States, the health and economic benefits of attaining the national goal for hypertension control would seem to merit a serious integrated effort.

Central effects of combined bendrofluazide and atenolol administration. A single dose study in normal subjects

Twelve normal male subjects received single oral doses of atenolol 100 mg (AT), bendrofluazide 5 mg (BFZ), combined atenolol 100 mg and bendrofluazide 5 mg (AT/BFZ), diazepam 5 mg (Dz), or one of two matching placebos, on each of 6 study days. Tests of psychomotor performance [digit symbol substitution (DSST), letter cancellation (LCT), continuous attention, choice reaction time (CRT), finger tapping, short-term memory, body sway], physiological measurements [critical flicker fusion (CFF), two-flash fusion (2FF)] and subjective assessments using visual analogue scales (VAS), were performed at 2 and 4 hours post-ingestion. Dz (active control) significantly worsened VAS scores at 2 h (+0.68) and reduced DSST scores at both 2 h (-15.0) and 4 h (-11.0). AT and BFZ given alone, each produced significant worsening of VAS at 2 h [AT +1.0; BFZ +1.38], but had no significant effects on performance. In combination however, AT/BFZ at 4 h produced significant impairment of DSST scores (-10.4), reduced finger tapping (-16.5) and increased involuntary rest pauses (+16.5). Despite these effects, no change in VAS scores occurred. In summary, we have demonstrated significant impairment of psychomotor performance in normal subjects with the AT/BFZ combination, which was not evident with the single agents and which occurred in the absence of a change in subjective awareness. These central effects may have important clinical implications for patients taking combined antihypertensive medication.

Angiotensin-converting enzyme inhibition as first-line treatment for hypertension

1. Perindopril (4 mg) was compared with atenolol (50 mg), captopril (25 mg b.d.) or a diuretic (hydrochlorothiazide 50 mg and amiloride 5 mg) in three studies involving a total of 503 hypertensive patients with a diastolic blood pressure (DBP) of 95-125 mmHg. 2. A 4 week single-blind placebo period preceded 12 weeks of active treatment. Dose titration was at weeks 4 and 8 if supine DBP greater than 90 mmHg. The dose was doubled and if necessary a diuretic was added in the atenolol or captopril comparisons, and atenolol was added in the diuretic study. 3. The fall in supine blood pressure (BP) was 27/17 mmHg with perindopril and 21/16 mmHg for atenolol. Monotherapy controlled 55% of patients on perindopril and 48% on atenolol, increasing to 78% and 58% with the addition of hydrochlorothiazide, respectively. Captopril caused a BP fall of 19/12 mmHg compared with 27/18 mmHg for perindopril, with 49% of both groups being controlled on monotherapy. 4. Diuretic addition produced a greater antihypertensive effect with perindopril (75%) compared with 57% for captopril in achieving control. Perindopril caused a comparable fall in supine BP to the diuretic combination 27/19 mmHg and 31/18 mmHg, but the fall in erect systolic BP was significantly greater for the diuretic. At 3 months, 85% of the diuretic group and 78% of the perindopril group achieved the target BP. 5. A multicentre trial of 856 patients treated with perindopril (690 patients treated for 1 year or more) has shown that BP control is maintained in the long term with a low incidence of side-effects (7.9%) causing withdrawal from treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation between dose of bendrofluazide, antihypertensive effect, and adverse biochemical effects

OBJECTIVE

To determine the relevant dose of bendrofluazide for treating mild to moderate hypertension.

DESIGN

Double blind parallel group trial of patients who were given placebo for six weeks and then randomly allocated to various doses of bendrofluazide (1.25, 2.5, 5, or 10 mg daily) or placebo for 12 weeks.

SETTING

General practices in Zealand, Denmark.

PATIENTS

257 Patients with newly diagnosed or previously treated hypertension, aged 25-70, who had a mean diastolic blood pressure of 100-120 mm Hg after receiving placebo for six weeks.

MAIN OUTCOME MEASURES

Reduction in diastolic blood pressure and changes in biochemical variables (potassium, urate, glucose, fructosamine, total cholesterol, apolipoprotein A I, apolipoprotein B, and triglyceride concentrations).

RESULTS

All doses of bendrofluazide significantly reduced diastolic blood pressure to the same degree (10-11 mm Hg). Clear relations between dose and effect were shown for potassium, urate, glucose, total cholesterol, and apolipoprotein B concentrations. The 1.25 mg dose increased only urate concentrations, whereas the 10 mg dose affected all the above biochemical variables.

CONCLUSION

The relevant range of doses of bendrofluazide to treat mild to moderate hypertension is 1.25-2.5 mg a day. Higher doses caused more pronounced adverse biochemical effects including adverse lipid effects. Previous trials with bendrofluazide have used too high doses.

Initial therapy for mild hypertension

The treatment of mild hypertension has been a subject of controversy because its benefits versus risks are not as well established as they are for moderate to severe hypertension. Results of several studies, however, now show that treatment reduces the frequency of stroke in those with milder blood pressure elevations. New guidelines published by the Joint National Committee recommend that treatment of mild hypertension begin with either a diuretic or a beta blocker. The effect on the most common complication of mild hypertension, that is, coronary heart disease (myocardial infarction and sudden cardiac death), has, however, not been encouraging in studies in which diuretics have been used as first-line treatment. Two large-scale primary preventive studies compared the efficacy of diuretics and beta blockers in reducing coronary heart disease in hypertensive patients; results were in favor of beta blocker regimens in men. So far there is some evidence, but no hard scientific proof, that certain beta blockers offer advantages over diuretics in preventing myocardial infarction and sudden cardiac death in hypertensive patients. A major concern with the use of diuretics is the risk of hypokalemia; this can be reduced when they are combined with beta blockers.