Only patients who have an artificial heart valve, have had endocarditis, or have had a heart transplant and developed a valve problem are advised to take antibiotics before having dental work or other procedures that might flood the bloodstream with bacteria, the Harvard Heart Letter said.

Some people born with heart problems may also need antibiotics depending on whether and how the defects were repaired, the newsletter added.

Since the 1950s, the AHA has urged some people to take antibiotics before having dental work to prevent infective endocarditis, a potentially serious infection of the heart’s lining.

However, after an analysis of the latest evidence, the AHA found no large trials have tested whether taking antibiotics before dental work actually prevents endocarditis.

If antibiotics do help, the effect is so small that the risk of side effects from the medication outweighs the benefits for most people, explains the Harvard Heart Letter.