Patient information: High blood pressure treatment in adults

HIGH BLOOD PRESSURE OVERVIEW

Hypertension is the medical term for high blood pressure. Untreated hypertension increases the strain on the heart and arteries, eventually causing organ damage. Hypertension increases the risk of heart failure, heart attack (myocardial infarction), and stroke. Fortunately, treatments for hypertension are effective and usually easy to take.

This topic will review the treatment of essential (also called primary) hypertension. Essential hypertension does not have a known underlying cause. Other topics about hypertension are also available. (See "Patient information: High blood pressure in adults" and "Patient information: High blood pressure, diet, and weight".)

LIFESTYLE CHANGES

Making lifestyle changes is an important first step in the treatment of high blood pressure. In some patients, lowering sodium and alcohol intake, keeping weight in the ideal range, engaging in regular aerobic exercise, and stopping smoking may be sufficient to control high blood pressure. (See "Patient information: High blood pressure, diet, and weight".)

However, many patients also require one or more medications to lower the blood pressure. The following is an overview of the different types of drugs that may initially be prescribed.

HIGH BLOOD PRESSURE MEDICATIONS

There are various medications that are commonly used to treat high blood pressure.

Although generally well tolerated, high blood pressure medications can cause side effects; the side effects depend upon the specific drug given, dosage, and other factors. Some people will respond well to one drug but not to another. Therefore, it may take time to determine the right drug(s) and proper dosage to effectively lower blood pressure with a minimum of side effects.

Diuretics — Diuretics lower blood pressure mainly by causing the kidneys to excrete more water and sodium, which reduces fluid volume throughout the body and widens (dilates) blood vessels.

The diuretics used to treat high blood pressure are thiazides (chlorthalidone, hydrochlorothiazide, and indapamide). In some cases, a potassium supplement or a potassium-sparing diuretic (amiloride, spironolactone, or triamterene) are given in combination with a thiazide diuretic because the thiazides can cause potassium deficiency because increased amounts of potassium are excreted in the urine.

Side effects — Side effects are uncommon with low doses of thiazide diuretics. Fatigue, dizziness, weakness, and other symptoms can occur as a result of decreased sodium, potassium, and water level. Other symptoms may include reversible impotence and gout attacks.

ACE inhibitors — Angiotensin converting enzyme (ACE) inhibitors block production of the hormone angiotensin II, a compound in the blood that causes narrowing of blood vessels and increases blood pressure. By reducing production of angiotensin II, ACE inhibitors allow blood vessels to widen, which lowers blood pressure and improves heart output.

The available ACE inhibitors include benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, and trandolapril.

Side effects — In some patients, ACE inhibitors cause a persistent dry hacking cough that is reversible when the medication is stopped. Less common side effects include dry mouth, nausea, lightheadedness, dizziness with standing, rash, muscle pain, or occasionally, kidney dysfunction.

A potentially serious complication of ACE inhibitors is angioedema, which occurs in 0.1 to 0.7 percent of people. People with angioedema rapidly (minutes to hours after taking the medication) develop swelling of the lips, tongue, and throat, which can interfere with breathing. These symptoms are a medical emergency and the ACE inhibitor should be discontinued.

Angiotensin II receptor blockers — The angiotensin II receptor blockers (ARBs) block the effects of angiotensin II on cells in the heart and blood vessels. Similar to ACE inhibitors, ARBs can widen blood vessels and lower blood pressure.

The available ARBs include candesartan, irbesartan, losartan, telmisartan, and valsartan.

Side effects — The main difference between ARBs and ACE inhibitors is that ARBs do not produce cough. Some people take angiotensin II receptor blockers experience dizziness, drowsiness, headache, nausea, dry mouth, abdominal pain, or other side effects. Angioedema is less common with ARBs than with ACE inhibitors.

Calcium channel blockers — Calcium channel blockers drugs reduce the amount of calcium that enters the smooth muscle in blood vessel walls and heart muscle. Muscle cells require calcium to contract. Thus, by inhibiting the flow of calcium across muscle cell membranes, calcium channel blockers cause muscle cells to relax and blood vessels to dilate, reducing blood pressure as well as reducing the force and rate of the heartbeat.

There are two major categories of calcium channel blockers:

• Dihydropyridines, including amlodipine, felodipine, isradipine, nicardipine, nifedipine, and nisoldipine
• Nondihydropyridines, including diltiazem and verapamil

Side effects — The side effects of calcium channel blockers vary with the specific agent used. Patients who take dihydropyridines may develop headache, dizziness, flushing, nausea, overgrowth of the gum tissue (gingival hyperplasia), or swelling of the extremities (peripheral edema).

Nondihydropyridines can occasionally cause the heart rate to slow too much. Other side effects may include headache and nausea with diltiazem or constipation with verapamil.

Beta blockers — Beta blockers block some of the effects of the sympathetic nervous system, which increases the heart rate and raises blood pressure with stress and/or activity. Beta blockers lower blood pressure in part by decreasing the rate and force at which the heart pumps blood.

The available beta blockers include acebutolol, atenolol, betaxolol, bisoprolol, carteolol, metoprolol, nadolol, penbutolol, pindolol, propranolol, and timolol.

Some beta blockers have combined activity, blocking both the beta and alpha receptors (see next section). These include labetalol and carvedilol.

Side effects — Beta blockers may worsen symptoms of asthma, other lung diseases, or blood vessel disease outside the heart (such as peripheral vascular disease). As a result, they normally are not prescribed for patients with such conditions. (See "Patient information: Claudication (peripheral arterial disease)".)

In addition, beta blockers may mask symptoms of low blood sugar (hypoglycemia) in people with diabetes who are treated with insulin. Beta blockers can also cause fatigue, dizziness, insomnia, a decreased ability to exercise, a slow heart rate, rash, and cold hands and feet due to reduced blood flow to the limbs.

Alpha blockers — Alpha blockers relax or reduce the tone of involuntary (ie, smooth) muscle in the walls of blood vessels (vascular smooth muscle), allowing the vessels to widen, thereby lowering blood pressure. An increase in blood vessel diameter is known as "vasodilation." The available alpha blockers include doxazosin, prazosin, and terazosin.

Side effects — Alpha blockers can cause dizziness, particularly when standing up, headache, weakness, drowsiness, low blood pressure when standing, or other side effects. They also may increase the risk of developing heart failure. For these reasons, they are not frequently used as a first-line treatment of essential hypertension. A possible exception is in an older man with symptoms related to enlargement of the prostate; such symptoms may be relieved by alpha blocker therapy. (See "Patient information: Benign prostatic hyperplasia (BPH)".)

Direct vasodilators — Direct vasodilators relax or reduce the tone of blood vessels. The two drugs in this class are hydralazine and minoxidil. Minoxidil is typically used in only severe or resistant high blood pressure.

Side effects — Side effects associated with direct vasodilators include headache, weakness, nausea, constipation, swelling in the lower legs, and rapid heartbeat. These effects are usually minimized by combining the vasodilator with a beta blocker. Minoxidil also may cause excessive hair growth. Rogaine, which is used to treat baldness, is a form of minoxidil that is applied to the skin.

THE PROPER HIGH BLOOD PRESSURE MEDICATION FOR YOU

A healthcare provider will take several factors into account when determining which antihypertensive drug should be tried first. In addition to considering the effectiveness and potential side effects, he or she will consider the person's general health, sex, age, and race; the severity of the high blood pressure; any additional, underlying medical conditions; and whether particular drugs should not be used.

Certain antihypertensive drugs are specifically recommended for the treatment of particular conditions, even if the person does not have high blood pressure. In many cases, a person with one of these conditions also has high blood pressure. As examples:

• An ACE inhibitor is recommended for people with diabetes mellitus who have increased levels of protein in the urine (proteinuria), heart failure, or a prior heart attack. (See "Patient information: Preventing complications in diabetes mellitus".)

• Beta blockers are recommended for people with heart failure or a prior heart attack. (See "Patient information: Heart failure treatments" and "Patient information: Heart attack recovery".)

• Beta blockers or calcium channel blockers are recommended to control symptoms in people with angina pectoris, which is temporary chest pain caused by an inadequate oxygen supply to heart muscle in patients with coronary artery disease. (See "Patient information: Angina treatment — medical therapy".)

There are also certain antihypertensive agents that are not recommended in some people. Some examples include:

• ACE inhibitors and ARBs (and many other medications not used to treat high blood pressure) are not recommended during pregnancy.
• Beta blockers may not be recommended for people with asthma or chronic lung disease and as primary therapy for high blood pressure, particularly in patients over age 60.

Finally, certain underlying medical conditions may be worsened by treatment with particular high blood pressure medications. As an example, diuretics can worsen gout. (See "Patient information: Gout".)

Thus, it is important to mention all current and previous medical problems to the healthcare provider to determine which medication is best.

Effectiveness and cardiovascular protection — There is no agreement about which class of drug should be used first. Evidence suggests that each of the four major classes of high blood pressure medications — diuretics, ACE inhibitors, calcium channel blockers, and beta blockers — is roughly equally effective, resulting in a good response in about 40 to 60 percent of cases. Lowering the blood pressure to the normal range protects against complications such as heart failure, stroke, and a heart attack.

Use of a particular drug may be better in certain situations. In a large clinical trial, people who were at increased risk for coronary artery disease had better outcomes when they were given a low-dose thiazide diuretic rather than an ACE inhibitor, calcium channel blocker, or beta blockers [1].

Recommendations — For people with high blood pressure who do not have any significant underlying medical condition (that is, uncomplicated high blood pressure), we recommend beginning first line treatment with a low dose of a thiazide diuretic, based upon their proven long-term benefit, improved outcomes compared to other drugs, and low cost.

If a low-dose thiazide alone is not effective in reducing blood pressure, experts recommend that an ACE inhibitor, ARB, calcium channel blocker, or beta blocker is added or substituted.

These general recommendations may be different for people with an underlying medical condition (eg, both an ACE inhibitor and a beta blocker are recommended for people with heart failure or a prior heart attack). In addition:

• A low dose thiazide diuretic provides better cardioprotection than an ACE inhibitor or a calcium channel blocker in younger and older people who have risk factors for coronary artery disease, including left ventricular hypertrophy (thickening of the heart muscle in response to high blood pressure), diabetes, current cigarette smoking, lipid abnormalities, or atherosclerotic cardiovascular disease.
• A diuretic is also recommended to prevent fluid accumulation in people with heart failure and in elderly people whose systolic blood pressure (the top number) is elevated. In elderly people, certain long-acting dihydropyridine calcium channel blockers may be an appropriate alternative.
• An ARB may be substituted for an ACE inhibitor in people who develop a persistent dry cough.
• An alpha blocker (eg, doxazosin, the longest-acting alpha blocker) may increase the risk of heart failure and is not usually recommended as a first-line therapy for high blood pressure. One possible exception may be in older men, who also have symptoms of an enlarged prostate, such as weak urine flow, frequent urination, and a sensation of insufficient bladder emptying. An alpha blocker may be effective in relieving these symptoms and reducing blood pressure.

Combination drug therapy — If a person does not respond adequately to the first high blood pressure medication, a second medication may be added. Other options include raising the dosage of the first drug to the maximum possible dose or adding a second drug after trying a moderate dosage of the first drug.

Adding a second drug may be:

• As or more effective than increasing the dose of the first drug.
• Associated with fewer side effects, many of which occur more frequently with higher doses

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: High blood pressure in adults
Patient information: High blood pressure, diet, and weight
Patient information: Claudication (peripheral arterial disease)
Patient information: Benign prostatic hyperplasia (BPH)
Patient information: Preventing complications in diabetes mellitus
Patient information: Heart failure treatments
Patient information: Heart attack recovery
Patient information: Angina treatment — medical therapy
Patient information: Gout

Professional Level Information:
Ambulatory blood pressure monitoring and white coat hypertension in adults
Can therapy be discontinued in well-controlled hypertension?
Cardiovascular risks of hypertension
Choice of therapy in essential hypertension: Recommendations
Diet in the treatment and prevention of hypertension
Hypertension: Who should be treated?
Indications for use of and contraindications to specific antihypertensive drugs
Overview of hypertension in adults
Patient adherence and the treatment of hypertension
Perioperative management of hypertension
Prehypertension and borderline hypertension
Resistant hypertension
Salt intake, salt restriction, and essential hypertension
Technique of blood pressure measurement in the diagnosis of hypertension
Treatment of hypertension in the elderly, particularly isolated systolic hypertension
What is goal blood pressure in treatment of hypertension?

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/highbloodpressure.html)

• National Heart, Lung & Blood Institute (NHLBI)

      (www.nhlbi.nih.gov/health/dci/Diseases/Hbp/HBP_WhatIs.html)

• American Heart Association

      (www.americanheart.org/presenter.jhtml?identifier=2114)

• The Hormone Foundation

       (www.hormone.org)

[1-6]