In which scenario would nitroglycerin NOT be indicated?

Nitroglycerin is a potent vasodilator commonly used to relieve angina and manage chest pain related to cardiac conditions. However, there are specific contraindications for its use due to potential serious adverse effects.

In the scenario where a patient has taken Viagra, or any similar PDE5 inhibitors, in the past 48 hours, administering nitroglycerin poses a significant risk for severe hypotension. This is because both medications cause vasodilation, and together they can lead to dangerously low blood pressure which can result in syncope or shock. Therefore, this situation indeed indicates that nitroglycerin should not be administered.

The other scenarios mentioned, while they may warrant caution, do not categorically contraindicate the use of nitroglycerin in the same way. Being hypertensive might lead to further evaluation before administering nitroglycerin, but it is not an absolute contraindication. Similarly, having taken nitroglycerin in the last 24 hours should also raise concerns regarding dosage and timing but is not an outright prohibition unless it's indicated as part of treatment for a current acute event.

Thus, the correct answer highlights the critical interaction between nitroglycerin and medications like Viagra, which dramatically increase the risk of adverse reactions.