Antidepressants may narrow the arteries of middle-aged men, potentially putting them at risk for heart attacks and stroke, researchers said.
A study involving 513 male twins, with an average age of 55, found those who took medications like Eli Lilly & Co.’s Cymbalta, Forest Laboratories Inc.’s Lexapro, or Pfizer Inc.’s Zoloft had thicker blood vessel walls. The increase, a measure of fatty-plaque buildup linked to atherosclerosis, was seen regardless of what type of antidepressant the men were taking.
The news seemed to have little impact on Indianapolis-based Lilly's stock. Shares dropped 2 cents Monday morning, to $34.97 each.
Cymbalta, Lilly's No. 2 seller, racked up $3.5 billion in sales in 2010, and some analysts say it may approach $5 billion annually before generic competition arrives in 2013.
Arteries naturally thicken with age, and each 10-micron increase is linked to a 1.8-percent higher risk of heart attack and stroke. Men taking antidepressants had a 41-micron thicker lining than their twin brothers who weren’t on medication, making their arteries appear about four years older. The difference was greatest in men who were depressed while taking the drugs, according to the study presented today at the American College of Cardiology meeting in New Orleans.
“Because we didn’t see an association between depression itself and a thickening of the carotid artery, it strengthens the argument that it is more likely the antidepressants than the actual depression that could be behind the association,” said lead researcher Amit Shah, a cardiology fellow at Emory University in Atlanta, in a statement.
The U.S. National Institutes of Health funded the study.
Antidepressants increase levels of brain chemicals including serotonin and norepinephrine, which may cause blood vessels to constrict, Shah said. The narrower opening may limit blood flow and boost hypertension, triggering atherosclerosis and heart disease, he said. Additional studies are needed to confirm whether the medications, the condition or other factors are responsible for the changes, he said.