Most people assume that when they take medications to lower their blood pressure, their chances of having a stroke also goes down to normal.

However, a new study finds that people on hypertension drugs can have stroke risk almost 2 1/2-times greater than those without high blood pressure. 

Stroke is the fifth-leading killer in the U.S., and the biggest cause of long-term disability. High blood pressure forces the heart to work harder, causing damage to blood vessels in the brain that can result in a stroke.

Taking blood pressure drugs is viewed as the best way to avoid stroke, but researchers at the University of Alabama report that the risk remains elevated despite medication. Also, the more drugs used to lower blood pressure, the higher the risk.

Their study involved 26,785 participants 45 and older. That group included 12,327 people with successfully controlled blood pressure (systolic upper number less than 140 mmHG) and 4,090 whose blood pressure was unsuccessfully treated. The researchers followed them for six years and found that more than 820 had suffered strokes.

Scientists found the risk of stroke went up by a third for each blood pressure medication taken. People who needed three or more medications were at a 248 percent higher risk than those whose normal systolic blood pressure was less than 120mmHG.

That risk is similar to people whose blood pressure is high but who are not taking any drugs to control it, researchers said.

The researchers said the study should not discourage people from taking blood pressure medication, but that it underscores that drugs are not the solution.

The best way to prevent a stroke is to eat healthy, lose weight, exercise, and restrict salt they say.