Blood pressure drug combination reduces heart attack deaths

Sep 16, 2008

Thousands of patients with high blood pressure could benefit from changing their drug treatment regimen to reduce their risk of cardiac death.

The current U.S. hypertension treatment guidelines recommend using a thiazide diuretic – a drug that increases the volume of urine – alone as the initial drug therapy for high blood pressure. But a failure of diuretic drugs to decrease deaths from heart attacks, an important consequence of hypertension, prompted Vanderbilt University Medical Center researchers to analyze data from existing clinical trials of diuretic drugs.

They found that combining a thiazide diuretic with a "potassium-sparing" drug to treat hypertension reduced both sudden cardiac death and total coronary mortality by 40 percent. The findings call into question the current treatment guidelines.

"The recommendations can now be re-examined in light of these new findings," said John Oates, M.D., senior author of the study published in the September/October issue of the Journal of the American Society of Hypertension. The Joint National Committee, under the direction of the National Heart, Lung, and Blood Institute, publishes clinical practice guidelines for hypertension – new guidelines are expected in 2009.

Thiazide diuretics successfully reduce blood pressure for many patients, but they are also known to deplete potassium, said Oates, a professor of Medicine and hypertension specialist. This potassium "wasting" has sparked concern over the years with studies suggesting a link between potassium loss and sudden cardiac death.

Oates and colleagues examined data from controlled clinical trials that compared a thiazide diuretic/potassium-sparing (ENaC inhibitor) drug combination to placebo. They generated new, previously unpublished data on sudden death in these trials, and then analyzed the results of the trials in a meta-analysis – a statistical evaluation of data combined from multiple trials. They found a 40 percent reduction in total cardiac mortality and in sudden cardiac death in elderly patients with hypertension taking the drug combination, compared with those receiving placebo.

"It was very striking," Oates said.

The investigators also performed a new meta-analysis of the clinical trials of thiazides given without a potassium-sparing drug, adding new trials to the mix. They found no benefit in coronary mortality and a 26 percent increase in sudden death. Even though the increase was not statistically significant, it was "going in the direction in which you didn't want to go," Oates said.

Observational studies previously had found an increase in sudden cardiac death in patients taking a thiazide diuretic alone, and one showed that sudden death was greater at higher doses of thiazides, he said. Studies in animal models of heart attacks also have demonstrated that low potassium levels (caused by thiazide diuretics) can spark the abnormal heart rhythms that lead to sudden death.

Do thiazide diuretics given alone have an adverse effect of increasing the risk of sudden cardiac death in patients with high blood pressure? It's possible.

"There's biologic plausibility for an adverse effect of the thiazides," Oates said. "If it's true, it's probably the largest adverse effect in the history of modern pharmacology. The number of individuals affected over the last 50 years would be staggering."

And since the current U.S. clinical practice guidelines for hypertension recommend a thiazide diuretic without a potassium-sparing drug, millions of patients may be at increased risk of coronary death, Oates pointed out.

Oates acknowledges that potassium-sparing drugs may reduce coronary mortality through a mechanism unrelated to their prevention of potassium loss. As studies proceed to determine how these drugs reduce death risk, he said, it's time to add them to thiazides as recommended first-line treatment for high blood pressure in the elderly.

Source: Vanderbilt University Medical Center

Explore further: Filipino tests negative for Middle East virus

add to favorites email to friend print save as pdf

Related Stories

US secretly created 'Cuban Twitter' to stir unrest

Apr 03, 2014

In July 2010, Joe McSpedon, a U.S. government official, flew to Barcelona to put the final touches on a secret plan to build a social media project aimed at undermining Cuba's communist government.

Call for truth in trans fats labeling by the FDA

Jan 03, 2011

Did you know that when you pick up a product promoted as trans fat free, you may still be ingesting a significant amount of this potentially harmful substance? An article by Case Western Reserve University School of Medicine ...

Faster testing of new pharmaceuticals

Jan 02, 2014

To improve medical treatment, researchers test new drug ingredients on biological cells. By combining two microscopy techniques, the time required for testing can be reduced by 50 to 80 percent. And far fewer ...

Recommended for you

Filipino tests negative for Middle East virus

1 hour ago

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

US orders farms to report pig virus infections

Apr 18, 2014

The U.S. government is starting a new program to help monitor and possibly control the spread of a virus that has killed millions of pigs since showing up in the country last year.

Foreigner dies of MERS in Saudi

Apr 18, 2014

A foreigner has died after she contracted MERS in the Saudi capital, the health ministry said on announced Friday, bringing the nationwide death toll to 73.

Vietnam battles fatal measles outbreak

Apr 18, 2014

Vietnam is scrambling to contain a deadly outbreak of measles that has killed more than 100 people, mostly young children, and infected thousands more this year, the government said Friday.

New clues on tissue scarring in scleroderma

Apr 18, 2014

A discovery by Northwestern Medicine scientists could lead to potential new treatments for breaking the cycle of tissue scarring in people with scleroderma.

User comments : 0

More news stories

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Study says we're over the hill at 24

(Medical Xpress)—It's a hard pill to swallow, but if you're over 24 years of age you've already reached your peak in terms of your cognitive motor performance, according to a new Simon Fraser University study.

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.