CHICAGO — Many older adults with high blood pressure can be treated less aggressively, which could mean taking fewer pills to get it under control, according to new treatment guidelines from an expert panel. But not all experts are on board with the advice — including the federal agency that appointed the group.

Panel members stressed they are not changing the definition of high blood pressure: 140 over 90. For adults 60 and older, they are recommending a higher treatment threshold, prescribing medicine only when blood pressure levels reach 150 over 90.

Too aggressive blood pressure treatment can cause fainting and falls in older patients, or bad interactions with drugs they’re already taking for other illnesses, panel members said.

The panel supports the lower target of 140 over 90 for younger adults — and for all adults who also have diabetes or kidney disease.

The guidelines released Wednesday are based on a review of the most rigorous kind of medical research — studies in which patients are randomly prescribed drugs or dummy pills — published since the last update in 2003. The research suggests older patients can avoid major health problems like heart attacks, strokes and kidney disease even when their blood pressure is above the current recommended level, the panel said.

For many patients, two or three drugs — or more — are needed to bring their blood pressure down. Many older adults could probably reduce their doses, or take fewer drugs, to reach the new, less strict target, said Dr. Paul James, a panel member and family medicine specialist-researcher at the University of Iowa.

While the guidelines were updated by a government-appointed panel, they don’t have the government’s endorsement like previous versions. The panel completed its work earlier this year, around the same time that the National Heart, Lung and Blood Institute announced that it was getting out of the guidelines business and turning the job over to the American Heart Association and American College of Cardiology. Updated guidelines from those medical groups are expected in late 2014.

In the meantime, the heart association is raising concerns about the new recommendations, saying the panel overlooked other evidence suggesting the 2003 government-backed recommendations are sound.