Blood pressure drugs need to match the situation
For some people, lifestyle measures are enough to keep blood pressure under control. But they’re not enough for everyone.
For one thing, “many patients are not willing to change their lifestyle,” says Dr. Peter Rudd, professor of medicine emeritus at the Stanford University School of Medicine.
A case in point: In one study of exercise and blood pressure, participants were expressly told to follow certain exercise regimes, and these led to blood pressure reductions. But the longer the trials were, the smaller the blood pressure reductions they yielded. The study authors speculated that over time participants lost interest or commitment and exercised less.
Other people can’t control their blood pressure even if they’re living lives of utter virtue. “Some people are already lean and active and eating right, and they still have high blood pressure,” Rudd says. “They need medication.”
What kind? Doctors are currently debating what drugs should be offered as first-in-line choices, with some calling for an overhaul of current guidelines.
But it also depends on what kind of high blood pressure you have.
* If you have high blood pressure because you retain fluids – which is common in people who are overweight – a diuretic should help. Diuretics work by eliminating excess fluid and sodium from the body.
“Letting out some fluid from the blood is like letting air out of a balloon,” says Emily Levitan, an assistant professor in the School of Public Health at the University of Alabama at Birmingham.
* If you have high blood pressure because your heart is over-exerting itself, a beta-blocker or calcium channel blocker may be a good choice. Beta blockers interfere with the hormone adrenaline, which accelerates the heart. Calcium channel blockers dilate the arteries, making it easier for the heart to pump blood through them.
* But maybe you have high blood pressure because your kidneys produce too much renin, an enzyme that sets off a chain of events that makes the body try to raise its own blood pressure by constricting blood vessels. In that case, you may need an angiotensin converting enzyme inhibitor (ACE inhibitor) or an angiotensin receptor blocker (ARB drug) – two drugs that help break the vessel-constricting cycle.
Guidelines for Taking Diuretics
Here are some general guidelines if you’re taking a diuretic:
Before a diuretic is prescribed, tell your doctor if you are taking any other medications that may have been prescribed by another physician or any over-the-counter or herbal remedies. Also, tell your doctor if you have any other medical problems.
Follow your doctor’s instructions on how often you should take the diuretic. If you are taking a single dose a day, it might be better to take it in the morning instead of at night, so that you will not have your sleep interrupted by frequent trips to the bathroom. (This is more pertinent for patients with congestive heart failure or patients with cirrhosis and portal hypertension). Talk to your doctor before changing the timing of your medications.
While taking a diuretic, have your blood pressure and kidney function tested regularly, as advised by your doctor.
Keep all appointments with your doctor and the laboratory so that your response to this drug can be monitored.
Just as lifestyle choices can work better in combinations, so too can some drug therapies. Partly that’s because high blood pressure can have more than one cause. But also, Rudd says, “when a patient starts on any one drug, the body starts to compensate.”
That is, if you lower your blood pressure one way, your body may sabotage itself by raising your blood pressure a new way.
Drugs must be matched with care so that they complement each other. That matching will depend on each patient’s individual circumstances.
Side effects are possible with all the drug options. Diuretics, for example, can lead to a loss of potassium. Beta blockers can reduce endurance, making them a poor choice for highly active people. Some drugs (for example, calcium channel blockers and another class of drugs called alpha blockers) have even been shown to increase the risk of heart failure and other serious cardiovascular problems even as they reduce blood pressure.
The most common side effect of diuretics is increased urination. This occurs most frequently in people taking loop diuretics. People who take diuretics may also have too much potassium in their blood (hyperkalemia) if they take a potassium-sparing diuretic, or too little potassium in their blood (hypokalemia) if they take a thiazide diuretic. Other side effects of diuretics may include: Low sodium in your blood (hyponatremia), Increased blood sugar, Increased cholesterol.
Types of Diuretics
There are 3 types of diuretic medicines. Each type works a little differently, but they all lower the amount of salt and water in your body, which helps to lower your blood pressure.
Thiazide diuretics are used to treat high blood pressure by reducing the amount of sodium and water in the body. Thiazides are the only type of diuretic that dilates (widens) the blood vessels, which also helps to lower blood pressure.
Because the science is evolving, periodically the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure issues guidelines for preferred high blood pressure treatment. The last ones were issued in 2003, and the next are expected this year.
Right now, the recommendations focus heavily on diuretics. They call for making a diuretic the first drug option when beginning treatment, including a diuretic in any treatment involving more than one drug and considering changing a treatment that doesn’t include a diuretic even if it has been successful at helping a patient reach goal level.
Only if patients can’t tolerate a diuretic does the committee recommend ACE inhibitors, calcium channel blockers and beta-blockers as alternatives.
These recommendations are based on the fact that diuretics are inexpensive, and yet they outperformed other tested drugs in preventing one or more major forms of cardiovascular disease in an eight-year trial known as ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial). Starting in 1994, the National Institutes of Health-funded study involved more than 40,000 high blood pressure patients age 55 and older.
But more recent studies contradict some of ALLHAT’s findings, leading many hypertension specialists to say a revamp in instructions is overdue.
One of those studies, called ACCOMPLISH, was published in the New England Journal of Medicine in 2008. It involved nearly 11,000 patients and compared two different combinations of drugs, both presented in a single pill: an ACE inhibitor with a calcium channel blocker and the same ACE inhibitor with a diuretic. It was funded by the drug company Novartis, one of a number of companies that make two-in-one blood pressure pills.
Both combinations succeeded in lowering blood pressure to goal levels for 80% of the patients, better results than in ALLHAT (60%) or among U.S. patients in general (30%). This implies that for high-risk patients, it may be wise to start with a combination of drugs, as opposed to the current practice of starting with one, usually a diuretic, and then adding on others if needed, says study lead author Dr. Kenneth Jamerson, professor of cardiovascular medicine at the University of Michigan in Ann Arbor.
But the most dramatic finding – one that made researchers stop the trial early – was this: Patients taking the ACE inhibitor/calcium channel blocker combination had 20% fewer heart attacks, strokes and other cardiovascular events than did patients taking the ACE inhibitor/diuretic combination.
Critics of the study say its results may not apply to high blood pressure patients in general. For one thing, patients in the study were older and sicker than average, notes Dr. Mitra Nadim, director of the Hypertension Center at USC.
Others note that much has happened in the field since the ALLHAT trial.
“Back then the question was: What was the best drug to start out with?” says Dr. Ronald Victor, director of clinical research at the Cedars-Sinai Heart Institute and director of the Cedars-Sinai Hypertension Center and a local spokesman for the American Heart Assn. “Now the question is: What’s the best combination to start with? . . . I think the ACCOMPLISH data are compelling.”
By Karen Ravn
Los Angeles Times