Which of the following is a contraindication to nitroglycerin?

• A. SBP > 180 mmHg
• B. Recent caffeine ingestion
• C. Hypotension (SBP < 90 mmHg or 30 mmHg below baseline)
• D. Age over 90

Answer: (C)

The main idea is recognizing when nitroglycerin cannot be used because it can drop blood pressure too much. Nitroglycerin mainly dilates veins, reducing preload, and at higher doses can lower afterload. In someone who already has very low blood pressure, giving it can cause a further dangerous drop in perfusion to the heart and brain. That’s why hypotension defined as systolic blood pressure less than 90 mmHg or a drop of 30 mmHg from baseline is a clear contraindication.

The other scenarios don’t carry the same immediate risk from nitro. Very high blood pressure isn’t a contraindication; while nitro is often used for angina, it isn’t forbidden in hypertensive patients. Recent caffeine ingestion doesn’t make nitroglycerin unsafe, though caffeine can influence vascular tone. Age by itself isn’t a contraindication either; drugs often require dose adjustments in the elderly, but age alone doesn’t preclude use.