Source: Sabrina Tavernise - The N.Y. Times ( Paid Registration )

The Food and Drug Administration on Tuesday toughened a warning it made last year about the potential risks of azithromycin, a commonly used antibiotic that can cause changes in the electrical activity of the heart that may lead to a fatal irregular heart rhythm in some patients.

Read Full Article: F.D.A. raises heart alert on antibiotic in wide use