The antidepressant Paxil has shown promise in strengthening the heart, new research suggests.

In a discovery that University of Michigan researcher John Tesmer, Ph.D., described as “completely serendipitous,” the drug paroxetine, a.k.a. Paxil, inhibits G protein-coupled receptor kinase 2. That’s a protein that becomes over-expressed when people have heart failure.

According to Tesmer, paroxetine improved the strength of the heart’s contractions in an animal model, without interfering with the heart rate. Although the drug is not currently prescribed in doses large enough to have a therapeutic effect, further development of the drug’s key compounds could yield leads within the next several years, researchers said.

The only caveat: SSRIs, often used to treat depression in nursing home residents, have been associated with an increased risk of falls in the elderly.

The study was published online in ACS Chemical Biology.