Final answer:
The contraindication to the administration of nitrates in a patient with a possible ST-segment elevation myocardial infarction (STEMI) and ongoing chest pain is the use of Phosphodiesterase inhibitors, due to the risk of severe hypotension.
Step-by-step explanation:
A patient with a possible ST-segment elevation MI (STEMI) experiencing ongoing chest pain or discomfort may need treatment with nitrates, such as nitroglycerin, to improve blood flow and alleviate symptoms. However, there are certain conditions that contraindicate the use of nitrates. Among the options provided, the contraindication to the administration of nitrates is D) Phosphodiesterase inhibitors. These medications, used most commonly for erectile dysfunction, can greatly potentiate the hypotensive effects of nitrates and can lead to dangerously low blood pressure, and therefore, patients who have taken phosphodiesterase inhibitors should not be given nitrates.
Other conditions that are contraindications for nitrate use include hypotension (low blood pressure), hypovolemia (decreased blood volume), and recent use of other vasodilatory medications, but these options are not listed among your choices. It's important to always review a patient's medical history, current medications, and the presenting symptoms carefully before administering any medication, including nitrates, for the treatment of acute cardiovascular events like STEMI.