Which pharmaceutical used for stress testing remains in the plasma the longest?

Dipyridamole is notable for its longer duration of action compared to other pharmaceuticals used in stress testing. This medication works by inhibiting the uptake of adenosine into cells, leading to an increase in the concentration of adenosine in the plasma, which in turn dilates coronary blood vessels.

The pharmacokinetics of dipyridamole result in a relatively extended half-life, allowing it to remain in the plasma longer than adenosine, regadenoson, or dobutamine. While adenosine has a very short half-life of only seconds due to its rapid metabolism, regadenoson, although longer than adenosine, is still shorter in duration than dipyridamole. Dobutamine, primarily used for patients who cannot undergo vasodilator stress tests, also has a different pharmacokinetic profile that leads to a shorter duration of effects compared to dipyridamole.

In scenarios where a lasting effect is desired for imaging purposes during a stress test, the extended plasma retention of dipyridamole makes it a preferred choice among the listed agents.