What is high blood pressure (hypertension)?

           High blood pressure or hypertension means high pressure (tension) in the arteries. Arteries are vessels that carry blood from the pumping heart to all the tissues and organs of the body. High blood pressure does not mean excessive emotional tension, although emotional tension and stress can temporarily increase blood pressure. Normal blood pressure is below 120/80; blood pressure between 120/80 and 139/89 is called "pre-hypertension," and a blood pressure of 140/90 or above is considered high.

          The top number, which is the systolic blood pressure, corresponds to the pressure in the arteries as the heart contracts and pumps blood into the arteries. The bottom number, the diastolic pressure, represents the pressure in the arteries as the heart relaxes after the contraction. The diastolic pressure reflects the lowest pressure to which the arteries are exposed. An elevation of the systolic and/or diastolic blood pressure increases the risk of developing heart (cardiac) disease, kidney (renal) disease, hardening of the arteries (atherosclerosis or arteriosclerosis), eye damage, and stroke (brain damage). These complications of hypertension are often referred to as end-organ damage because damage to these organs is the end result of chronic (long duration) high blood pressure. For that reason, the diagnosis of high blood pressure is important so efforts can be made to normalize blood pressure and prevent complications.

          It was previously thought that rises in diastolic blood pressure were a more important risk factor than systolic elevations, but it is now known that in people 50 years of age and older systolic hypertension represents a greater risk. The American Heart Association estimates high blood pressure affects approximately one in three adults in the U.S. High blood pressure also is estimated to affect about two million U.S. teens and children, and the Journal of the American Medical Association reports that many are underdiagnosed. Hypertension is clearly a major public health problem.

Which lifestyle modifications are beneficial in treating high blood pressure?

          Lifestyle modifications refer to certain specific recommendations for changes in habits, diet and exercise. These modifications can lower the blood pressure as well as improve a patient's response to blood pressure medications.

Alcohol

          People who drink alcohol excessively (over two drinks per day*) have a one and a half to two times increase in the prevalence of hypertension. The association between alcohol and high blood pressure is particularly noticeable when alcohol intake exceeds five drinks per day. The connection is a dose-related phenomenon. In other words, the more alcohol consumed, the stronger is the link with hypertension.
*The National Institute on Alcohol Abuse and Alcoholism considers a standard drink to be 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of 80-proof distilled spirits. Each contains roughly the same amount of absolute alcohol -- approximately one-half ounce or 12 grams.

Smoking  

          Although smoking increases the risk of vascular complications (for example, heart disease and stroke) in people who already have hypertension, it is not associated with an increase in the development of hypertension. But cigarette smoking can repeatedly produce an immediate, temporary rise in the blood pressure of 5 to10 mm Hg. Steady smokers however, may have a lower blood pressure than nonsmokers. The reason for this is that nicotine in cigarettes causes a decrease in appetite, which leads to weight loss. This, in turn, lowers blood pressure.

Coffee and caffeinated beverages

          In one study, the caffeine consumed in 5 cups of coffee daily caused a mild increase in blood pressure in elderly people who already had hypertension, but not in those who had normal blood pressures. The combination of smoking and drinking coffee in persons with high blood pressure may increase the blood pressure more than coffee alone. Limiting caffeine intake and cigarette smoking in hypertensive individuals may be of some benefit in controlling high blood pressure.
The American Heart Association states that there is no consistent evidence that daily consumption of 1 to 2 cups of coffee (or its equivalent) increases blood pressure to any significant degree in people who do not already have high blood pressure.
However, a study reported in the Journal of the American Medical Association in 2005 found that while coffee consumption was not associated with an increased risk of hypertension, consumption of sugared or diet cola did cause modest increases in blood pressure, though no recommendations on cola consumption were made.
Energy drinks often contain high levels of caffeine. The American Heart Association points to research which suggests people with high blood pressure or heart disease should avoid energy drinks because they could affect their blood pressure.

Salt

           The American Heart Association recommends that consumption of dietary salt be less than 6 grams of salt per day in the general population and less than 4 grams for people with hypertension. To achieve a diet containing less than 4 grams of salt, salt is not added to food or when cooking. The amount of natural salt in the diet can be reasonably estimated from the labeling information provided with most purchased foods. Note: Some salt substitutes contain sodium, the substance in salt that increases blood pressure!

Other dietary considerations

It is beneficial to add potassium to the diet. Studies show that people who consume more potassium have lower blood pressures. Good sources of potassium include:

1. bananas,
2. melons,
3. oranges,
4. spinach and
5. zucchini.

Along with lowering salt in the diet, a balanced eating plan that also reduces cholesterol intake and fatty foods is recommended. The TLC Diet (Therapeutic Lifestyle Changes) often is recommended to lower blood cholesterol.
Some supplements, such as garlic and flaxseed have been shown in studies to lower blood pressure. Some small-scale studies have shown Coenzyme Q10 (CoQ10) may lower blood pressure, but further studies are needed. Garlic may react with some prescription medications such as blood thinners, so consult a physician before taking any supplements. Other home remedies, such as calcium, magnesium, and fish oil have been shown in studies to lower blood pressure, but patients should consult with their physician before taking any supplements.

Obesity

          Being overweight can increase the risk for high blood pressure. Obesity is common among hypertensive patients, and its prevalence, especially in aging patients, can contribute to hypertension in several ways. In obese people the heart has to pump more blood to supply the excess tissue. The increased cardiac output can then raise the blood pressure. In addition, obese hypertensive individuals have a greater stiffness (resistance) in their peripheral arteries throughout the body. Insulin resistance and the metabolic syndrome, which are associated with hypertension, also occur more frequently in the obese. Finally, obesity may be associated with a tendency for the kidneys to retain salt. Weight loss may help reverse obesity-related problems and may lower blood pressure. Losing as little as 10 to 20 pounds can help lower blood pressure and the risk of heart disease.

          The American Journal of Clinical Nutrition reported in 2005 that waist size, a measure of central body obesity, was a better predictor of a person's blood pressure than body mass index (BMI), a measure of overall obesity. Men should strive for a waist size of 35 inches or under and women 33 inches or under. Some very obese people have a syndrome called sleep apnea, which is characterized by periodic interruption of normal breathing during sleep. Sleep apnea may contribute to the development of hypertension in this subgroup of obese individuals. Repeated episodes of apnea cause a lack of oxygen (hypoxia), causing the adrenal gland to release adrenaline and related substances which cause a rise in the blood pressure.

Exercise and stress reduction

          A regular exercise program may help lower blood pressure over the long term. Activities such as jogging, bicycle riding, power walking, or swimming for 30 to 45 minutes daily may lower blood pressure by as much as 5 to15 mm Hg. There also appears to be a relationship between the amount of exercise and the degree to which the blood pressure is lowered. So the more one exercises (up to a point), the more they lower their blood pressure. This beneficial response occurs only with aerobic (vigorous and sustained) exercise programs. Any exercise program should be recommended or approved by a physician.

          Stress reduction can also help lower blood pressure. Stress can be limited by determining priorities, using time management skills, saying "no," living by values, setting realistic goals, and improving self-esteem. Relaxation methods to reduce stress include deep breathing, progressive muscle relaxation, mental imagery relaxation, relaxing to music, yoga, meditation, and biofeedback.
It is important for patients to keep logs of their blood pressure through the day. Physicians may have patients chart their blood pressure in a daily log to see if stressful factors during the day cause blood pressure to go up.
Patients should be sure to get adequate sleep in order to relax their minds and bodies. Naps may be necessary.

How is high blood pressure treated?

Goals of treatment
           High blood pressure usually is present for years before its complications develop. Ideally, hypertension is treated early before it damages critical organs in the body. Increased public awareness and screening programs to detect early, uncomplicated hypertension are keys to successful treatment. Successful early treatment of high blood pressure can significantly decrease the risk of stroke, heart attack, and kidney failure.

           The goal for patients with combined systolic and diastolic hypertension is to attain a blood pressure of 140/85 mm Hg. Although lifestyle changes in prehypertensive patients are appropriate, it is not well established that treatment with medication of patients with prehypertension is beneficial.

Starting treatment for high blood pressure

           Blood pressure persistently higher than 140/90 mm Hg usually is treated with lifestyle modifications and medication. These circumstances include borderline diastolic pressures in association with end-organ damage, systolic hypertension, or factors that increase the risk of cardiovascular disease, such as age over 65 years, African American descent, smoking, hyperlipemia (elevated blood fats), or diabetes.
Any one of several classes of medications may be started, except the alpha blocker medications, which are used only in combination with another antihypertensive medication in specific medical situations. (See the next section for a more detailed discussion of each of the several classes of antihypertensive medications.)
In some situations, certain classes of antihypertensive drugs are preferable to others as the first-line (preferred first-choice) drugs. Angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blocking (ARB) drugs are the drugs of choice in patients with heart failure, chronic kidney failure (in diabetics or nondiabetics), or heart attack (myocardial infarction) that weakens the heart muscle (systolic dysfunction). Also, beta blockers are sometimes the preferred treatment in hypertensive patients with a resting tachycardia (racing heart beat when resting) or an acute (rapid onset) heart attack.

           Patients with hypertension may sometimes have a co-existing second medical condition. In such cases, a particular class of antihypertensive medication or combination of drugs may be chosen as the first-line approach. The idea in these cases is to control the hypertension while also benefiting the second condition. For example, beta blockers may treat chronic anxiety or migraine headache as well as hypertension. Also, the combination of an ACE inhibitor and an ARB drug can be used to treat certain diseases of the heart muscle (cardiomyopathies) and certain kidney diseases where reduction in protein in the urine would be beneficial.

           In other situations, certain classes of antihypertensive medications should not be used. Dihydropyridine calcium channel blockers used alone may cause problems for patients with chronic renal disease by increasing proteinuria. However, an ACE inhibitor will blunt this effect. The non-dihydropyridine type of calcium channel blockers should not be used in patients with heart failure. However, these drugs may be beneficial in treating certain arrhythmias. Some drugs, such as minoxidil, may be relegated to second- or third-line choices for treatment. Clonidine is an excellent drug but has side effects such as fatigue, sleepiness, and dry mouth making it a second- or third-line choice. See the section below on pregnancy for the antihypertensive drugs that are used in pregnant women.

Treatment with combinations of drugs for high blood pressure

           The use of combination drug therapy for hypertension is common. At times, using smaller amounts of one or more drugs in combination can minimize side effects while maximizing the anti-hypertensive effect. For example, diuretics, which also can be used alone, are more often used in a low dose in combination with another class of antihypertensive medications. This way, the diuretic has fewer side effects while improving the blood pressure-lowering effect of the other drug. Diuretics also are added to other antihypertensive medications when a patient with hypertension has fluid retention and swelling (edema).

           A useful combination is that of a beta blocker with an alpha blocker in patients with high blood pressure and enlargement of the prostate gland in order to treat both conditions simultaneously. Caution is necessary when combining two drugs that both lower the heart rate. For example, patients receiving a combination of a beta blocker to a non-dihydropyridine calcium channel blocker (for example, diltiazem [Cardizem, Dilacor, Tiazac] or verapamil [Calan, Verelan, Isoptin, Covera-HS]) need to be monitored carefully to avoid an excessively slow heart rate (bradycardia). Combining alpha and beta blockers such as carvedilol (Coreg) and labetalol (Normodyne, Trandate) is useful for cardiomyopathies and for hypertension patients.

Emergency treatment for high blood pressure

          In a hospital setting, injectable drugs may be used for emergency treatment of hypertension. The most commonly used are sodium nitroprusside (Nipride), labetalol (Normodyne), and nicardipine (Cardene). Emergency medical therapy is needed for patients with severe (malignant) hypertension and in patients with short duration (acute) congestive heart failure, dissecting aneurysm (dilation or widening) of the aorta, stroke, and toxemia of pregnancy.

Treatment during pregnancy

           Pregnant women may develop hypertension or may have it before conception. These patients have an increased risk of developing preeclampsia or eclampsia (toxemia of pregnancy). These conditions usually develop during the last 3 months (third trimester) of pregnancy. In preeclampsia, which can occur with or without pre-existing hypertension, affected women have hypertension, protein loss in the urine (proteinuria), and swelling (edema). In eclampsia, seizures also occur and the hypertension requires emergency treatment. The baby must be delivered quickly as part of the treatment of the mother. The main goal of treating the high blood pressure in toxemia is to keep the diastolic pressure below 105 mm Hg in order to prevent a brain hemorrhage or seizures in the mother.
Hypertension that develops before the 20th week of pregnancy almost always is due to pre-existing hypertension and not toxemia. High blood pressure that occurs only during pregnancy, called gestational hypertension, may start late in the pregnancy. Women with gestational hypertension do not have proteinuria, edema, or convulsions, and there appears to be no ill effects on the mother or fetus. This form of hypertension resolves shortly after delivery, although it may recur with subsequent pregnancies.

          The use of medications for hypertension during pregnancy is controversial. The risk of untreated mild to moderate hypertension to the fetus or mother during pregnancy probably is not very great. Lowering the blood pressure too much can interfere with the flow of blood to the placenta and impair fetal growth. Not all mild or moderate hypertension during pregnancy needs to be treated with medication. If it is treated, the blood pressure should be reduced slowly and not to very low levels.
Antihypertensive agents used during pregnancy need to be safe for normal fetal development. Beta blockers, hydralazine (a vasodilator), labetalol (Normodyne, Trandate), alpha-methyldopa (Aldomet), and more recently, calcium channel blockers have been approved as suitable medications for hypertension during pregnancy. Some antihypertensive medications are not recommended (contraindicated) during pregnancy. These include ACE inhibitors, ARB drugs, and diuretics. ACE inhibitors may aggravate a diminished blood supply to the uterus (uterine ischemia) and cause kidney dysfunction in the fetus. ARB drugs may lead to death of the fetus. Diuretics can cause depletion of blood volume and impair placental blood flow and fetal growth.

Which medications are used to treat high blood pressure?

Angiotensin converting enzyme inhibitors (ACE Inhibitors) and angiotensin receptor blockers

The angiotensin converting enzyme (ACE) inhibitors and the angiotensin receptor blocker (ARB) drugs both affect the renin-angiotensin hormonal system which helps regulate blood pressure. ACE inhibitors act by blocking (inhibiting) an enzyme that converts the inactive form of angiotensin in the blood to its active form. The active form of angiotensin constricts or narrows the arteries, but the inactive form cannot. With an ACE inhibitor as a single drug treatment (monotherapy), 50 to 60 percent of Caucasians usually achieve good blood pressure control. African American patients also may respond, but they may require higher doses and frequently do best when an ACE inhibitor is combined with a diuretic. (See the discussion of diurectics that follows.)
As an added benefit, ACE inhibitors may reduce an enlarged heart (left ventricular hypertrophy) in patients with hypertension. These drugs also appear to slow the deterioration of kidney function in patients with hypertension and protein in the urine (proteinuria). They have been particularly useful in slowing the progression of kidney dysfunction in hypertensive patients with kidney disease resulting from type 1 diabetes (insulin-dependent). ACE inhibitors usually are the first-line drugs to treat high blood pressure in patients who also have congestive heart failure, chronic kidney failure, and heart attack (myocardial infarction) that weakens the heart muscle (systolic dysfunction). ARB drugs currently are recommended for first-line kidney protection in diabetic nephropathy (kidney disease).
Patients treated with ACE inhibitors who also have kidney disease should be monitored for further deterioration in kidney function and high serum potassium. These drugs may be used to reduce the loss of potassium in people who are being treated with diuretics that cause patients to lose potassium. ACE inhibitors have few side effects, but the most common is a chronic cough. Occasionally, there may be fluid retention (edema). The ACE inhibitors include:

• enalapril (Vasotec),
• captopril (Capoten),
• lisinopril (Zestril and Prinivil),
• benazepril (Lotensin),
• quinapril (Accupril),
• perindopril (Aceon),
• ramipril (Altace),
• trandolapril (Mavik),
• fosinopril (Monopril), and
• moexipril (Univasc).

For patients who develop a chronic cough on an ACE inhibitor, an ARB drug is a good substitute. ARB drugs work by blocking the angiotensin receptor (binder) on the arteries to which activated angiotensin must bind to have its effects. As a result, the angiotensin is not able to work on the artery. (Angiotensin is a hormone that constricts the arteries.) ARB drugs appear to have many of the same advantages as the ACE inhibitors but without the associated cough; however, edema still may occur. They are also suitable as first-line agents to treat hypertension.
ARB drugs include:

• losartan (Cozaar),
• irbesartan (Avapro),
• valsartan (Diovan),
• candesartan (Atacand),
• olmesartan (Benicar),
• telmisartan (Micardis), and
• eprosartan (Teveten).

In patients who have hypertension in addition to certain second diseases, a combination of an ACE inhibitor and an ARB drug may be effective in controlling the hypertension and also benefiting the second disease. This combination of drugs can treat hypertension and reduce the loss of protein in the urine (proteinuria) in certain kidney diseases and perhaps help strengthen the heart muscle in certain diseases of the heart muscle (cardiomyopathies). Both the ACE inhibitors and the ARB drugs are not to be used (contraindicated) in pregnant women. (See the section above on pregnancy.)

Beta blockers

The sympathetic nervous system is a part of the nervous system that helps to regulate certain involuntary (autonomic) functions in the body such as the function of the heart and blood vessels. The nerves of the sympathetic nervous system extend throughout the body and exert their effects by releasing chemicals that travel to nearby cells in the body. The released chemicals bind to receptors (molecules) on the surface of the nearby cells and stimulate or inhibit the function of the cells. In the heart and blood vessels, the receptors for the sympathetic nervous system that are most important are the beta receptors. When stimulated, beta-receptors in the heart increase the heart rate and the strength of heart contractions (pumping action). Beta-blocking drugs acting on the heart slow the heart rate and reduce the force of the heart's contraction.
Stimulation of beta-receptors in the smooth muscle of the peripheral arteries and in the airways of the lung causes these muscles to relax. Beta blockers cause contraction of the smooth muscle of the peripheral arteries and thereby decrease blood flow to body tissues. As a result, the patient may experience coolness in the hands and feet. In response to the beta blockers, the airways are squeezed (constricted) by the contracting smooth muscle; this squeezing (impingement) on the airway causes wheezing, especially in individuals with a tendency for asthma.
Beta blockers remain useful medications in treating hypertension, especially in patients with a fast heartbeat while resting (tachycardia), cardiac chest pain (angina), or a recent heart attack (myocardial infarction). Beta blockers appear to improve long-term survival when given to patients who have had a heart attack. Whether beta blockers can prevent heart problems (are cardioprotective) in patients with hypertension any more than other antihypertensive medications is uncertain. Beta blockers may be considered for treatment of hypertension because they also may treat co-existing medical problems, such as chronic anxiety or migraine headaches. Common side effects of these drugs include depression, fatigue, nightmares, sexual impotence in males, and increased wheezing in people with asthma.
The beta blockers include:

• atenolol (Tenormin),
• propranolol (Inderal),
• metoprolol (Toprol),
• nadolol (Corgard),
• betaxolol (Kerlone),
• acebutolol (Sectral),
• pindolol (Visken),
• carvedilol (Coreg)
• penbutolol (Levatol), and
• bisoprolol (Zebeta).

  Diuretics

  Diuretics are among the oldest known medications for treating hypertension. They work in the tiny tubes (tubules) of the kidneys to promote the removal of salt from the body. Water also may be removed along with the salt. Diuretics may be used as single drug treatment (monotherapy) for hypertension. More frequently low doses of diuretics are used in combination with other antihypertensive medications to enhance the effect of the other medications.
  The diuretic hydrochlorothiazide (HydroDIURIL) works in the far end (distal) part of the kidney tubules to increase the amount of salt that is removed from the body in the urine. In a low dose of 12.5 to 25 mg per day, this diuretic may improve the blood pressure-lowering effects of other antihypertensive drugs, and the low doses also can prevent the fluid retention (edema) associated with ACE and ARB drugs. The idea is to treat the hypertension without causing adverse effects sometimes seen with higher doses of hydrochlorothiazide. These side effects include potassium depletion and elevated levels of triglyceride (fat), uric acid, and glucose (sugar) in the blood.
  Occasionally, when salt retention causing accumulation of water and swelling (edema) is a major problem, the more potent 'loop' diuretics may be used in combination with other antihypertensive medications. The loop diuretics are so called because they work in the loop segment of the kidney tubules to eliminate salt.
  The most commonly used diuretics to treat hypertension include hydrochlorothiazide (HydroDIURIL) and chlorthalidone, the loop diuretics furosemide (Lasix) and torsemide (Demadex), the combination of triamterene and hydrochlorothiazide (Dyazide), and metolazone (Zaroxolyn). For individuals who are allergic to sulfa drugs, ethacrynic acid, a loop diuretic, is a good option. Diuretics generally should not be used in pregnant women. (See the preceding section on pregnancy.)

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Previous contributing author: Dwight Makoff, MD