The Food and Drug Administration is preparing to warn doctors of the risks associated with certain imaging agents used to help view the heart in an echocardiography following reports of serious heart problems and even deaths in patients injected with the drugs.

The two agents involved are Bristol-Myers Squibb’s Definity (perflutren lipid microsphere) and General Electric’s Optison (perflutren).

Spokeswoman for the FDA, Karen Riley, said the agency had been investigating reports of deaths and serious cardiopulmonary reactions after people were injected with either of the products. “The agency will soon be issuing information to healthcare professionals to alert them to these serious risks and to provide guidance regarding the safe use” of the drugs, Riley told the Wall Street Journal.

These diagnostic contrast medicines, which are made from gases enclosed in tiny capsules of protein or fatty material, are injected into a patient’s vein to give a clearer picture of the heart during ultrasound examinations. The gas leaves the body after just a few minutes. But while millions of people have echocardiograms each year, only a small group of them receive Definity or Optison, the FDA reports.

Black-box warning

The agency has also asked manufacturers to update their product labelling, and there are unconfirmed reports that the drugs will be expected to carry a black-box warning instructing doctors not to use them in patients with unstable angina, acute heart attacks and unstable cardiopulmonary disease. The label is also expected to tell doctors to monitor patients’ heartbeats for half an hour after the ultrasound examination has been carried out.

Bristol-Myers Squibb spokesman, Tony Plohoros, confirmed the company was in discussions with the FDA about label revisions for Definity and said BMS “will communicate them as soon as they are final”. Sales of Definity were approximately $65 million in 2006

General Electric has also confirmed it is in talks with the FDA about changing the label for Optison. The drug was withdrawn from the market in late 2005 following manufacturing problems, however the company had been expected to resume selling it this autumn.