July 25, 2005-- Posted at 4:05 PM CDT
(HealthDay News) -- More than two-thirds of the 65 million Americans with high blood pressure require two or more anti-hypertensive drugs to manage their condition. Many of these people also take medicines for high cholesterol and diabetes.
That makes for a heaping mound of pills to swallow every day.
"Anybody can take a few drugs for a few months, but these people have to be on drugs indefinitely," said Dr. John D. Bisognano, an associate professor of medicine and director of cardiac rehabilitation and clinical preventive cardiology at the University of Rochester Medical Center in Rochester, N.Y.
But there is encouraging news on the horizon for people with high blood pressure. Easier-to-take medications and novel drugs and devices promise to improve long-term hypertension management. Basic research continues to sort out the causes of hypertension. And vigorous prevention initiatives aimed at sparing children from this chronic health problem breed hope for future generations of Americans.
Hypertension, often called "the silent killer," usually occurs without symptoms but remains a leading risk factor for stroke, heart attack, heart failure and kidney disease. The only way to find out if you have it is to have a blood pressure reading.
High blood pressure is literally the force exerted as blood pumps into the arteries through the circulatory system and as the arteries resist the flow of blood, says the American Heart Association. Systolic pressure, the "upper" number in a blood pressure test, measures the force when your heart is beating; the "lower" diastolic number reflects the pressure when the heart is resting between beats.
A normal blood pressure for adults is less than 120 mmHg over less than 80 mmHg, and a reading of 140/90 mmHg or higher is considered high, requiring medical intervention.
In 2003, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure, a panel convened by the federal government, added a new blood pressure category, called "prehypertension" -- to put people on warning about the potential risk they face. Prehypertension is defined as a pressure of 120-139/80-89 mmHg.
For people with diabetes or kidney disease, the goal is to reduce blood pressure to 130/80 mmHg.
"One of the problems you run into is people who are at the highest risk -- the people with diabetes and kidney disease -- often require lots of medications to get their blood pressure down, because every medication gives you about a 10- to 15-point drop or so," Bisognano said.
"If you're starting at 200 and need to go to 130, that's a lot of medications," he added.
No single medication has proved to be the magic bullet for lowering blood pressure, so doctors typically rely on a number of different pharmaceuticals, including diuretics, angiotensin receptor blockers, angiotensin converting enzyme inhibitors, beta blockers and calcium channel blockers.
Pharmaceutical developers are responding to the need to make it easier for hypertensive patients to comply with medication regimens by developing new combination products. In the future, we will see more fixed-dose combos of antihypertensive medications as well as pills that can treat more than one risk factor at a time, predicts LeadDiscovery, a United Kingdom-based research outfit.
Pfizer Inc. was the first to offer such a two-in-one product. In 2004, the company received approval from the U.S. Food and Drug Administration to begin marketing Caduet, a pill that contains both Norvasc for lowering high blood pressure and Lipitor for treating high cholesterol.
There are a few new agents in the pipeline that hold promise. One novel class of medications, called oral Renin inhibitors, works by targeting an enzyme released by the kidneys that can affect blood pressure. The first of these agents to be introduced on the market is likely to be Aliskiren, a Novartis drug currently in phase III testing. Analysts expect the company to seek regulatory approval in 2006 and are forecasting blockbuster sales topping $1 billion by 2008 and reaching $3.6 billion by 2012, LeadDiscovery reports.
Meantime, even a gadget to keep blood pressure at bay is being tested. In March, doctors at the University of Rochester Medical were the first in the nation to implant the Rheos, a battery-operated generator that activates the body's natural blood pressure regulation systems. Much like a pacemaker regulates heart rhythm, this device stimulates nerves in the carotid arteries to tell the brain to reduce blood pressure. Bisognano is part of the team that is testing the device.
Still, preventing hypertension in the first place is a far better thing than having to rely on medicines or machines, clinicians agree. That is why the National Hypertension Association (NHA) has focused on basic research and education.
NHA researchers have shown, for example, that salt-sensitive rats get high blood pressure when exposed to excess salt. "But the salt resistant ones are not bothered by it at all; their kidneys get rid of it," noted Dr. William M. Manger, NHA chairman and clinical professor of medicine at New York University Medical Center. At least in salt-sensitive rats, it appears that excess salt to the brain causes hypertension, he said. How that will play out in humans is still unknown, but investigators are hopeful.
The NHA also sponsors VITAL (Values Initiative Teaching About Lifestyle), a rapidly expanding school-based initiative to change the lifestyle and behavior of young children. It focuses on nutrition and exercise, a much broader agenda than hypertension alone. But it fills a critical gap, according to Manger, author of the not-yet-released book, Our Greatest Threats Protect Your Children and Yourself, focusing on preventing unhealthy lifestyles.
"I think this VITAL program is the best thing we could do for our nation," he said.
By Karen Pallarito, HealthDay Reporter
The American Heart Association has more facts about high blood pressure (www.americanheart.org ).
SOURCES: John D. Bisognano, M.D., Ph.D., associate professor, medicine, and director, cardiac rehabilitation and clinical preventive cardiology, University of Rochester Medical Center, Rochester, N.Y.; William M. Manger, M.D., Ph.D., chairman, National Hypertension Association, and clinical professor, medicine, New York University Medical Center, New York City; May 2003 Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure; LeadDiscovery, Sussex, England; American Heart Association, Dallas; Caduet Web site, Pfizer Inc., New York City; April 1, 2005, press release, University of Rochester Medical Center
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