Nitroglycerin is contraindicated in patients:

Nitroglycerin is contraindicated in patients:

• A. With a systolic blood pressure less than 120 mm Hg.
• B. Who have taken up to two doses.
• C. Who have experienced a head injury.
• D. With a history of an ischemic stroke.

Answer: (C)

Preserving adequate cerebral perfusion after a head injury is crucial. Nitroglycerin lowers blood pressure by dilating veins and reducing preload, which can decrease overall mean arterial pressure. In someone with head trauma, this drop in perfusion pressure can worsen brain injury or increase intracranial pressure, so nitroglycerin is avoided in that situation. The other scenarios aren’t absolute contraindications: a systolic blood pressure threshold of less than 120 mm Hg isn’t a universal rule against use (nitro is usually avoided if pressure is too low to maintain perfusion, but 120 isn’t the defining limit). Taking up to two doses aligns with typical nitroglycerin use for ongoing chest pain. A history of an ischemic stroke by itself does not prohibit nitroglycerin administration, though clinicians always consider individual risks.

Preserving adequate cerebral perfusion after a head injury is crucial. Nitroglycerin lowers blood pressure by dilating veins and reducing preload, which can decrease overall mean arterial pressure. In someone with head trauma, this drop in perfusion pressure can worsen brain injury or increase intracranial pressure, so nitroglycerin is avoided in that situation.

The other scenarios aren’t absolute contraindications: a systolic blood pressure threshold of less than 120 mm Hg isn’t a universal rule against use (nitro is usually avoided if pressure is too low to maintain perfusion, but 120 isn’t the defining limit). Taking up to two doses aligns with typical nitroglycerin use for ongoing chest pain. A history of an ischemic stroke by itself does not prohibit nitroglycerin administration, though clinicians always consider individual risks.