If you're one of the roughly 75 million Americans with high blood pressure (hypertension), you might like to believe that lifestyle changes,

such as losing weight, exercising and cutting back on salt, can control it. In some cases, it can. But like it or not, most people who have hypertension end up on medication.

The problem is that more than one-third of patients on medication still have elevated blood pressure readings. In many instances, they are not on medication or a dosage that is right for them. Millions also are suffering from avoidable side effects.

There are more than 60 drugs for hypertension--too many for most physicians (even specialists) to know about in detail. What's more, your drug treatment needs to be targeted to match the cause of your hypertension.

What’s Your Hypertension?

Of the millions of Americans with inadequately controlled hypertension, nearly all could have blood pressure in the normal range simply by adjusting their medication. What most patients don't realize is that hypertension is driven by different mechanisms that respond to different treatments.

The three mechanisms underlying hypertension in most cases and the best treatments for each…

#1: Hypertension driven by sodium/volume.

This is the most common form of high blood pressure, affecting at least half of hypertensive patients.

The kidneys do not excrete sodium efficiently and, as a result, the body starts to accumulate sodium and fluid. This increase in fluid volume raises blood pressure. In addition, elevated sodium can trigger arterial constriction in some patients, which further raises blood pressure.

Telltale signs: Fluid retention in the legs (edema) and low levels of the hormone renin (as measured with a widely available blood test). African-Americans, people over age 65 and those who are "salt-sensitive are more likely to have sodium/volume hypertension.

Main treatment: A diuretic (water pill that increases sodium excretion or a calcium-channel blocker, such as amlodipine (Norvasc), that dilates arteries.

#2: Hypertension driven by the renin-angiotensin system (RAS).

The kidneys have sensors that monitor blood pressure and blood volume. When either is low, the kidneys secrete the hormone renin, which triggers the formation of angiotensin II, constricting arteries and raising blood pressure.

Telltale signs: High renin levels in the blood, the absence of edema and lack of response to diuretics prescribed to reduce blood pressure. It's more common in Caucasians under age 50.

Four classes of drugs that block RAS activation…

  • Angiotensin-converting enzyme (ACE) inhibitors, such as enalapril (Vasotec) and captopril (Capoten).
  • Angiotensin-receptor blockers (ARBs), such as losartan (Cozaarand valsartan (Diovan.
  • Direct renin inhibitor (DRI). Aliskiren (Tekturna)—the only drug within this new class.
  • Beta-blockers, an older drug class, which includes metoprolol (Toprol). In most patients with RAS-mediated hypertension, ACE inhibitors and ARBs are preferred over beta-blockers-outcomes are better, and they cause fewer side effects, such as fatigue.

Approximately 80% of hypertension patients will respond to drugs that target sodium/volume or the RAS, or to a combination of drugs that targets both.

#3: Hypertension driven by the sympathetic nervous system (SNS). The SNS is responsible for hypertension in about 15% of cases and frequently is overlooked by physicians. Stimulation of the SNS, which is the primary link between our brain and our blood pressure, results in adrenaline-induced increases in heart rate and cardiac output (the amount of blood pumped by the heart) and arterial constriction. Emotions stimulate the SNS and may be the source of SNS hypertension.

Effective drugs include beta-blockers, which slow down the heart, often in combination with an alpha-blocker, such as doxazosin (Cardura), which dilates arteries. Drugs like clonidine Catapres), a central alpha-receptor stimulator, reduce SNS outflow from the brain but cause fatigue in most patients.

Telltale signs: Conditions such as alcohol abuse and sleep apnea can trigger SNS-driven hypertension. Other indicators are episodic hypertension and hypertension that is not controlled by drugs that target sodium/volume and the RAS.

Prescription Pitfalls

There are many effective drugs on the market, but unless they are correctly prescribed, hypertension won't be controlled and avoidable side effects may occur. Common errors you should watch out for…

  • Widespread overtreatment. Millions of Americans are on more medication than they need, including many people who might not need any at all.

The most common reasons doctors overprescribe: Anxiety that raises blood pressure when visiting the doctor, incorrect measurement of blood pressure at the doctor's office and/or at home, and the addition of medication in patients with well-controlled hypertension who have an occasional elevated reading.

  • Not enough diuretics. In many people, a low dose of a diuretic, such as 25 mg of bydrochlorothiazide, is sufficient-a higher dose is not needed and even can be harmful. But in some, a higher dose or a combination of two diuretics is essential Studies show that in half of people with uncontrolled hypertension, blood pressure can be brought under control by strengthening the diuretic regimen.
  • Underuse of some highly effective older drugs. New drugs are promoted, while some older drugs are nearly forgotten. Older diuretics such as amiloride (Midamor) and forsemide (Demadex), and beta-blockers such as betaxolol (Kerlone) and bisoprolol (Zebeta) are examples of excellent older drugs that are not commonly prescribed but should be.
  • Overuse of beta-blockers. Beta-blockers can cause fatigue and, in older patients, can affect cognitive function. Modifying or eliminating use of the beta-blocker can improve cognitive function in some patients and should not be overlooked as a consideration in the evaluation of cognitive decline. Many patients taking a beta-blocker for hypertension don't need to be on one!
  • Lack of appreciation for emotional factors. Decades of studies have failed to prove that such factors as stress, anger and anxiety lead to hypertension. However, some studies suggest that repressed emotions, the emotions we are unaware of, might contribute. If your hypertension is driven by emotional factors, you will respond better to drugs that target the SNS.

Summing up, nearly all patients with hypertension can be treated successfully with available drugs. The goal is a normal blood pressure without drug side effects. You should not settle for less.

Should you see a hypertension specialist? If your hypertension is under control with one or two drugs, and you have no side effects, you don't need to see a specialist.

Otherwise, consider seeking the opinion of a physician specializing in hypertension. To find one, go to www.asb-us.org, the Web site of the American Society of Hypertension (under "Patients," click on "HTN Specialists Directory”).

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