Download Scientific Reference Guide: Hypertension

Scientific Reference Guide Hypertension
Description of Condition
In the United States, 65 million people are estimated to have high blood pressure (BP) or hypertension.
Hypertension is often referred to as the “silent killer” because it usually has no signs or symptoms. If left
untreated, it can cause heart failure, aneurysms (bulging of the vessels), myocardial infarction, stroke,
kidney failure, peripheral arterial disease, and blindness. The treatment of hypertension is important
because every 20-mm Hg increase in systolic blood pressure (SBP) or 10-mm Hg increase in diastolic BP
across the entire BP range is associated with a doubling in the risk of cardiovascular disease.
According to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation,
and Treatment of High Blood Pressure, the target BP in patients with hypertension is less than 140/90 mm
Hg, or less than 130/80 mm Hg in hypertensive patients who also have diabetes or renal disease. The diagnosis of hypertension is made when the mean of two or more properly measured, seated, BP readings is
140/90 mm Hg or higher on at least two separate occasions. Clinicians should be alert to the possibility
of secondary hypertension (due to renal parenchymal disease, renal arterial disease, adrenal disease, aortic
coarctation, drug abuse) and should screen for these conditions in selected cases.
Nonprescription Interventions
Achieving BP goals generally relies on lifestyle modification as well as use of antihypertensive medication.
Restricting salt and eating a diet rich in fruits, vegetables, potassium, fiber, low-fat dairy products, and
polyunsaturated fats decreases BP in people with hypertension. In overweight or obese people, a 10-kg
weight loss reduces SBP by 5 to 20 mm Hg. Aerobic exercise and cognitive/relaxation therapy can reduce
SBP by 4 to 9 mm Hg. More modest reductions in BP can be achieved with resistance exercise training.
Home BP monitoring and self-management education programs can assist in controlling elevated BP
levels. Alcohol should be limited to one drink per day for women and two drinks daily for men. Lifestyle
modification, when used alone, should only be utilized for a relatively brief time prior to beginning
antihypertensive therapy if BP is not controlled.
Categories of Prescription Pharmaceutical Treatments (i.e., Drug Classes)
Intraclass Comparisons
Diuretics
■ High-dose thiazide diuretics (>25 mg/day) have more adverse metabolic effects than low-dose diuretics.
Beta-Blockers
■ As initial or add-on therapy, no one beta-blocker has demonstrated superiority in terms of efficacy in
lowering BP or improving quality of life in hypertensive patients.
■ There are no data suggesting that one beta-blocker is superior to another for any subgroup of patients,
based on demographic characteristics, other medications, or comorbidities.
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Scientific Reference Guide Hypertension
Calcium channel blockers
■ Based on available evidence, there are no differences in BP lowering among amlodipine, diltiazem,
isradipine, nicardipine, nifedipine, nisoldipine, and verapamil (no studies were identified for felodipine and bepridil).
■ Short-acting calcium channel blockers (e.g., nifedipine) have been associated with a dose-related
increase in myocardial infarctions and mortality. When calcium channel blockers are chosen, a longacting agent is preferred.
Angiotensin-converting enzyme inhibitors
■ Cough occurs in up to 10% of patients taking angiotensin-converting enzyme (ACE) inhibitors, and
angioedema in up to 2%, but the incidence is higher among blacks and Asians.
Interclass Comparisons
■ Based on cardiovascular outcomes data, low-dose thiazide diuretics are considered first-line treatment
for most patients with hypertension.
■ Doses of hydrochlorothiazide and chlorthalidone above 25 mg/day are not generally recommended,
although the greatest clinical experience is with hydrochlorothiazide doses from 25 to 50 mg/day.
(Chlorthalidone is dosed from 12.5 to 25 mg/day.)
■ The lowest rate of drug discontinuation due to adverse events among patients taking antihypertensive
agents is with diuretics and angiotensin receptor blockers (ARBs; 3% each).
■ Both beta-blockers and methyldopa are useful for managing hypertension during pregnancy.
■ Among antihypertensive agents, calcium channel blockers are associated with the highest rates of
discontinuation owing to adverse events (7%).
■ In diabetic patients, and compared with other antihypertensive agents, dihydropyridine calcium
channel blockers (amlodipine, felodipine, nifedipine) are associated with similar reductions in cardiac
risk and total mortality but a higher risk of heart failure.
■ Used alone, calcium channel blockers or diuretics are more effective than ACE inhibitors for lowering
BP among blacks. However, most patients will require two or more drugs.
■ The combination of an ACE inhibitor and thiazide diuretic reduces the risk of stroke in patients who
have had a cerebrovascular event.
■ Combination antihypertensive therapy with an ACE inhibitor and an ARB provides small incremental reductions in BP, but cannot be recommended for routine use until more studies are performed.
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Scientific Reference Guide Hypertension
Conclusion
Most patients with hypertension will require lifestyle modification plus at least two antihypertensive drugs.
In the absence of a compelling indication, most patients should start with a thiazide diuretic, as the overall evidence supports the use of low-dose diuretics as the primary agent for treating hypertension in terms
of reducing mortality and morbidity from vascular disease and events. ACE inhibitors or calcium channel
blockers (long-acting) are good alternatives when a diuretic does not control BP or cannot be used.
An alternative to an ACE inhibitor is an ARB. Beta-blockers are generally recommended when there is a
compelling clinical reason such as coronary ischemia and/or prior myocardial infarction. Most patients,
particularly those with initial BPs of 160/100 mm Hg or greater (or 20/10 mm Hg above goal), will require
two or more agents to reduce BP levels to less than 140/90 mm Hg.
Methods Note
This scientific reference guide is a product of the Prescription Drug Information Project, a collaborative venture between the University of California (UC) and the California HealthCare Foundation. This summary is
based on two reports on the effectiveness and safety of beta-blockers and calcium channel blockers
performed by the Drug Effectiveness Review Project (DERP). The DERP report is based on a rigorous method
of systematic literature reviews, ensuring inclusion of relevant studies of high quality. Another team of
researchers at UC Davis prepared a supplementary report on other drug and nondrug treatments for hypertension. Both reports (DERP and UC Davis) were reviewed by two outside experts and subsequently evaluated by a panel of highly regarded physicians and pharmacists from the UC. The reports are available at
www.chcf.org.
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