FDA warns of risk of myocardial infarction and death with use of certain cardiac stress test drugs

On November 20, 2013, the US Food and Drug Administration (FDA) issued a warning concerning the rare risk of myocardial infarction (MI) and death with use of the cardiac nuclear stress test agents Lexiscan (regadenoson) and Adenoscan (adenosine). The FDA has approved changes to the drug labels to reflect these serious events and has updated its recommendations for use of these agents. The FDA has reviewed the FDA Adverse Event Reporting System (FAERS) database and the medical literature for cases of MI and death from all causes associated with the use of Lexiscan and Adenoscan. Information about Lexiscan included that dating from June 24, 2008, to April 10, 2013, and for Adenoscan, from May 18, 1995, to April 10, 2013. The beginning dates correlated with the start of marketing for each drug. The FAERS database contained 26 MI cases and 29 cases of death occurring after Lexiscan administration, and 6 cases of MI and 27 cases of death after Adenoscan administration. Reports did not always specify when deaths or MIs occurred. When reported, these adverse events tended to occur within 6 hours after Lexican or Adenoscan administration. A few deaths occurred when Lexiscan or Adenoscan was administered with exercise stress testing, which is not an FDA approved use of the drugs. With Lexiscan, the most common adverse events associated with death were cardiac arrest, MI, loss of consciousness, respiratory arrest, electrocardiography ST-segment depression, pulmonary edema, and ventricular fibrillation. With Adenoscan, the most common adverse events associated with death were cardiorespiratory arrest, dyspnea, cardiac arrest, respiratory arrest, and ventricular tachycardia. A review of the medical literature also identified 2 case reports of MI associated with Lexiscan use. However, published studies from the medical literature have not documented an increased incidence of cardiovascular adverse events with Lexiscan compared with Adenoscan. Lexiscan and Adenoscan are FDA approved for use during cardiac nuclear stress tests in patients who cannot exercise adequately. Both products help identify coronary artery disease by dilating these arteries and increasing blood flow to help identify obstructions. Lexiscan and Adenoscan cause blood to flow preferentially to the healthier, unblocked, or unobstructed arteries, which can reduce blood flow in obstructed arteries. In some cases, this reduced blood flow can lead to an MI, which can be fatal. The use of both drugs should be avoided in patients with signs or symptoms of unstable angina or cardiovascular instability because these patients may be at greater risk for serious cardiovascular adverse reactions. Cardiac resuscitation equipment and trained staff should be readily available before administering Lexiscan or Adenoscan.