What are the contraindications of administering nitroglycerin?

Contraindications for administering nitroglycerin include severe hypotension (systolic blood pressure <90 mmHg), use of phosphodiesterase inhibitors (such as sildenafil) within the last 24-48 hours, and known hypersensitivity to nitrates. Additionally, it should be avoided in patients with aortic stenosis or increased intracranial pressure. Administering nitroglycerin in these conditions can lead to serious complications, including further hypotension and adverse reactions.