Expensive brand-name medications to lower blood pressure are no better at preventing cardiovascular disease than older, generic diuretics, says new data from a landmark study.

Dr. Paul Whelton reported the results on Aug. 13 at the plenary session of the China Heart Congress and International Heart Forum, in Beijing. Whelton is president and CEO of Loyola University Health System and chairman of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), which examined the comparative value of different blood pressure-lowering medications.

In the study, more than 33,000 patients with high blood pressure were randomly assigned to take either a diuretic (chlorthalidone) or one of two newer drugs, a calcium channel blocker (amlodipine) or an ACE inhibitor (lisinopril).

In 2002, ALLHAT researchers reported that among patients followed for four to eight years, the diuretic was better than the calcium channel blocker in preventing heart failure and better than the ACE inhibitor in preventing stroke, heart failure, and overall cardiovascular disease.

In the new study, researchers followed ALLHAT participants for an additional four to five years after completion of the trial, bringing the total follow-up period to between eight and 13 years. During this longer follow-up period, the differences between the three drugs narrowed—by most measures they finished in a statistical dead heat.

Yet, the diuretic still was superior in two measures: Compared with the diuretic group, the ACE inhibitor group had a 20 percent higher death rate from stroke, and the calcium channel blocker group had a 12 percent higher rate of hospitalizations and deaths due to heart failure.

Diuretics, sometimes called "water pills," are the traditional medications for high blood pressure. They cause kidneys to remove sodium and water from the body, thereby relaxing blood vessel walls. ACE inhibitors such as lisinopril (brand names Prinivil and Zestril) decrease chemicals that tighten blood vessels. Calcium channel blockers such as amlodipine (brand name Norvasc) relax blood vessels.

Diuretics cost $25 to $40 per year, while newer brand-name hypertension drugs can cost $300 to $600 per year.

The National Heart, Lung and Blood Institute recommends that patients control their blood pressure by first controlling their weight, exercising, reducing sodium, increasing potassium, and drinking alcohol in moderation. The institute says that if lifestyle changes aren't sufficient, diuretics then normally should be the drug of first choice.

Newer, higher-priced drugs are heavily marketed, however, and diuretics account for only about 30 percent of prescriptions written for high blood pressure medications, Whelton says.

Whelton is senior author of a study published in the May 24 issue of Archives of Internal Medicine that found using techniques similar to those employed by pharmaceutical sales reps can help persuade doctors to prescribe diuretics. Like drug sales representatives, researchers in the study met with small groups of doctors, especially opinion leaders. They detailed guidelines for treating high blood pressure, and handed out studies, newsletters, exam-room posters, and other like items. An examination of prescribing patterns found that the technique, known as "academic detailing," influenced what drugs doctors prescribed.

ALLHAT is sponsored by the National Heart, Lung and Blood Institute. "We are continuing to mine data that we collected during the trial," Whelton says.