The American Heart Association classifies normal blood pressure as less than 120/80 millimeters of mercury (mm Hg). In prehypertension, a person’s blood pressure is higher than normal, but not high enough to be considered hypertensive (140/90 mm Hg or higher). Prehypertension often leads to full-blown hypertension , and is associated with increased risks of cardiovascular disease. The current recommendations for managing prehypertension include maintaining a healthful weight, exercising, and eating a healthful diet. But these recommendations have done little to slow the growing problem of prehypertension.

A new study published March 14, 2006 by the New England Journal of Medicine found that treating prehypertension with the medication candesartan reduced the risk of developing full-blown hypertension for up to four years.

About the Study

This study included 772 people with prehypertension, defined as having either a systolic blood pressure (the “top number”) of 130-139 mm Hg and a diastolic pressure (the “bottom number”) of less than 90 mm Hg, or systolic pressure less than 140 mm Hg and diastolic pressure 85-89 mm Hg. The participants were randomly assigned to receive the angiotensin-receptor blocker candesartan (Atacand) or a matching placebo pill daily for two years. For an additional two years, all participants took a daily placebo pill. The participants had regular blood pressure measurements, and the researchers tracked which participants progressed to having full-blown hypertension, defined as a single blood pressure reading of 160/100 mm Hg or higher, or three readings of 140/90 mm Hg or higher.

After two years of taking the medication, the participants in the candesartan group were 66.3% less likely to have developed full-blown hypertension than those in the placebo group. At year four, participants in the candesartan group were still 15.6% less likely to have developed full-blown hypertension than the placebo group. There was no significant difference in the likelihood of having adverse events between the candesartan group and the placebo group.

These results must be interpreted with caution, since the study was funded and organized by AstraZeneca, the pharmaceutical company that manufacturers candesartan. Also, the results would have been more reliable if the researchers followed the participants longer, to see if the medication reduced the risk of developing cardiovascular disease.

How Does This Affect You?

These findings suggest that using candesartan to treat prehypertension may help prevent or postpone the development of full-blown hypertension. In this study, two years of treatment resulted in a reduction in risk of developing hypertension for up to four years.

Does this study mean that everyone with prehypertension should take candesartan? Not just yet. More studies are needed to determine the long-term safety and effectiveness of medications for treating prehypertension. But these promising results do suggest that medications may soon be an option—in addition to lifestyle changes—to help slow the progression from prehypertension to full-blown hypertension.