Displaying 2 results of Guanfacine Stable Isotopes Guanfacine is a medication used to treat attention deficit hyperactivity disorder (ADHD) and hypertension. Guanfacine stable isotopes are the non-radioactive forms of this medication, primarily used in scientific research and medical testing. These isotopes have the same chemical and physical properties as the natural form of guanfacine, but with a unique atomic weight, making them useful in tracking and identifying the drug in biological samples.