Why Diet Drug Phen/Fen Damaged The Heart

A new study published in the December 5 issue of the American Heart Association's journal Circulation explains some of the underlying mechanisms about why the diet drug damaged the heart. Led by researchers from Case Western Reserve University's School of Medicine and the National Institute of Drug Abuse, the study screened fen, phentermine (phen), and several other drugs to see if they activated neurotransmitter receptors that can damage hearts.

Fen and two migraine drugs, ergotamine and methysergide, which also are known to cause heart valve damage, were found to activate the serotonin receptor known as 5-HT2B located on heart's valves (both the mitral and aortic). Serotonin is a neurotransmitter that affects a range of behaviors, including feeding, sleep and mood regulation.

According to Bryan L. Roth, associate professor of biochemistry, psychiatry and neurosciences at CWRU, and the paper's senior author, the findings suggest that activation of 5-HT2B receptors may be necessary to produce heart valve damage.

"The study points to a need for all potential medications to be screened to see if they engage the 5-HT2B receptor before passing approval. This is of great public health importance," Roth said.