What is contraindicated for use in a patient with COPD undergoing a chemical stress test?

In the context of a patient with COPD (Chronic Obstructive Pulmonary Disease) undergoing a chemical stress test, the use of adenosine is contraindicated primarily due to its potential to cause bronchospasm. Adenosine is a vasodilator that can lead to significant bronchoconstriction in patients with reactive airways, which is a common characteristic of COPD. The risk of inducing bronchospasm or exacerbating breathing difficulties makes adenosine a particularly poor choice for stress testing in these patients.

Dobutamine and regadenoson are alternatives that can be used safely in patients with respiratory issues. Dobutamine works by increasing cardiac output through inotropic effects without triggering bronchospasm. Regadenoson, on the other hand, is a selective A2A receptor agonist that is less likely to cause bronchial constriction compared to adenosine.

Exercise treadmill tests, although requiring physical exertion, might also be suitable depending on the patient's functional capacity and level of COPD severity, as they can be monitored closely and adapted to individual limitations.

Thus, adenosine stands out as contraindicated specifically for its potential adverse effects on respiratory function in COPD patients, making it the correct choice in this scenario.