Regadenoson is the international nonproprietary name (INN) of an agent that is used in the fight against coronary heart disease and other cardiovascular problems. The Food and Drug Administration (FDA), the agency of the United States Department of Health and Human Services responsible for regulating medications, approved it on 10 April 2008. The European Union, though, has not yet granted regadenoson an approval. Astellas Pharma Inc., a pharmaceutical company founded in Japan in 2005, markets the drug under the trade name Lexiscan.
Regadenoson is promoted as the first pharmacologic stress agent manufactured as a rapid-injection dose contained in a pre-filled syringe. Pharmacologic stress agents refer to substances or drugs used for measuring how well the heart can respond to external stress. Chemical compounds that are commonly used in pharmacologic stress testing include adenosine, dobutamine and dipyridamole. In regadenoson's case, adenosine is used.
Regadenoson is referred to as an adenosine A2A receptor, or ADORA2A. This makes it an adenosine receptor specifically used for coronary artery vasodilation, which involves relaxing smooth muscle cells to permit the widening of these particular blood vessels. This leads to hyperaemia, which is an increase of blood flow to, or excessive blood accumulation in, a certain part of the body. Notably, regadenoson possesses a two- to three-minute biological half-life, while that of adenosine is measured at only 30 seconds.
Regadenoson comes as an 0.4-milligram solution meant for intravenous administration and single use. The time of injection into a peripheral vein is rapid, lasting less than 10 seconds. A 5-milliliter saline flush then follows to clean and sterilize the intravenous line.
Ten to 20 seconds after the saline flush, a radionuclide myocardial perfusion imaging agent is introduced to illustrate the function of the heart muscle, or myocardium. Regadenoson's ability to induce hyperaemia particularly aids radionuclide myocardial perfusion imaging. Since the effects of regadenoson does not depend on the weight of the patient, there is no need to set doses according to this characteristic.
The FDA places regadenoson in the pregnancy category C of its classification of fetal risks from pharmaceuticals. Pregnancy category C is a middling classification, representing a higher risk than categories A and B, but lower than D and X. Such a classification of this particular substance means that although fetal risk has been shown in animal reproductive studies, it is ultimately fine for pregnant women to use due to its potential benefits and a lack of controlled studies in human beings.
