In a series of presentations at the 22nd annual meeting of the American Society of Hypertension, doctors demonstrated that use of two high blood pressure medications from two different classes regularly outperformed single-gun therapy for a disease that affects more than 65 million Americans.

"We find substantial evidence to broaden the use of combination therapy as an initial strategy for the treatment of hypertension," Kenneth Jamerson, professor of internal medicine at the University of Michigan in Ann Arbor, told United Press International.

In one study, researchers showed that a strategy of offering once-daily fixed doses of combinations is capable of getting as many as 80 percent of patients in the United States to their treatment goal.

"These are unprecedented figures," Jamerson said. "Only about 37 percent of Americans who are taking high blood pressure medication are achieving their treatment goals."

In the "Avoiding Cardiovascular Events through Combination Therapy in Patients Living with Systolic Hypertension" (ACCOMPLISH) trial, Jamerson and colleagues rounded up more than 11,000 patients who were being treated for high blood pressure but whose systolic blood pressure remained above 140 mmHg and whose diastolic blood pressure was above 90 mmHg or were high-risk for heart attack or stroke.

The patients were taken off their current medication and put on a combination dose of either amlodipine combined with benazepril, or amlodipine combined with hydrochlorothiazide.

Amlodipine is a calcium channel blocker; benazepril is an angiotension converting enzyme-inhibitor, and hydrochlorothiazide is a diuretic.

The study was designed to determine if there is a difference in long-term outcomes depending on which drug combination is used, but Jamerson said the preliminary data he was discussing shows that it is feasible to get patients' blood pressure under control with aggressive dosing.

In the international trial, more than 75 percent of patients achieved that blood pressure goal after 18 months of treatment. The study will continue at least another year before the final outcomes are revealed.

Researchers in other trials also showed that when it comes to treating high blood pressure, more is better. In two trials, doctors combined amlodipine with the angiotension receptor blockers valsartan or olmesartan and came up with similar conclusions: The combined drugs were able to get better blood pressure control than individual treatment.

Both combinations, amlodipine and valsartan -- to be marketed by Novartis as Exforge -- and a duo of amlodipine and olmesartan -- to be sold by Daiichi Sankyo as Azor -- are not yet available in the United States.

"Exforge represents a very favorable combination of valsartan and amlodipine," Joseph Izzo Jr., professor of medicine at the State University of New York at Buffalo, told UPI. "This can be applied widely instead of, or after monotherapy for patients not previously controlled."

In his trial, 894 patients who were unsuccessful in controlling blood pressure on any single drug were switched to either a combination of amlodipine 5 mg and valsartan 160 mg (443 patients), or the same combination, but using amlodipine 10 mg (451 patients).

Overall, 81.3 percent of the patients on the 5/160 formulation of Exforge achieved the blood pressure goal at week 16, compared with 87.6 percent of patients on the 10/160 dose, Izzo said. "The outcomes were very favorable in all populations tested and at both doses. All were very well tolerated and the blood pressure control was consistent across all groups."

The second trial involved 1,940 patients with mild to severe hypertension who were divided into 12 different groups and got either placebo or amlodipine by itself, olmesartan by itself or six different doses of combination therapy.

"All combinations of amlodipine and olmesartan produced significantly greater mean reductions in both diastolic and systolic blood pressure than either medication alone," said Steven Chrysant, clinical professor of medicine at the University of Oklahoma in Oklahoma City.

In the study, the patients on a high dose of the drug Azor saw the biggest reduction in their blood pressure -- 19.4 mmHg -- and all active agents, monotherapy or combination were significantly superior to placebo, Chrysant said.

In yet another example of the move to combination dosing, researchers said the long-term treatment of patients on a combination of aliskerin -- Novartis' Tekturna -- and the diuretic hydrochlorothiazide produced no falloff in effectiveness in an extension trial.

"Patients were able to maintain the 9 mmHg reduction in diastolic blood pressure and the 16 mmHg drop in systolic blood pressure that was seen at the end of one year for another four months," Alan Gradman, chief of cardiology at the Western Pennsylvania Hospital in Pittsburgh, told UPI.

"Treatment with aliskerin in combination with hydrochlorothiazide provided sustained blood pressure-lowering over at least 12 months in patients with mild to moderate hypertension," Gradman said.

He noted that Novartis filed this week for U.S. approval of the combination product.

"Combination therapy in one tablet appears to be the way to go in treating patients with high blood pressure," Suzanne Oparil, president of the society and professor of medicine at the University of Alabama at Birmingham, told UPI.

She said a lot of the success of the combination products will depend on how health insurers react to the products. She said third-party payers may want doctors to order two generic drugs rather than the combination product.

However, she said that it is well known that outcomes are better when a patient only has to take one pill instead of two.