Which factors must be confirmed before giving nitroglycerin for chest pain?

• A. Ischemic chest pain symptoms, SBP ≥ 100 mmHg, no recent PDE-5 inhibitors, and no contraindications such as suspected RV infarct
• B. Pain scale 0-10
• C. Water consumption history
• D. History of diabetes

Answer: (A)

The key idea is safety criteria for administering nitroglycerin in chest pain. Nitroglycerin helps by dilating veins and reducing the heart’s preload, which lowers myocardial oxygen demand, but it can cause dangerous drops in blood pressure if used when the patient isn’t a good candidate.

First, chest pain should be consistent with ischemia (myocardial infarction or unstable angina) so that nitroglycerin is actually helping the underlying problem rather than treating nonischemic pain. If the pain isn’t ischemic, nitro won’t address the cause and could delay other needed care.

Second, the patient’s systolic blood pressure needs to be at least 100 mmHg. Nitro lowers blood pressure, primarily by reducing preload. If the pressure is too low, further vasodilation could compromise perfusion to vital organs or trigger shock.

Third, recent use of phosphodiesterase inhibitors (such as certain ED medications or PAH treatments) is a contraindication. These drugs and nitroglycerin can interact to cause a dangerous, excessive drop in blood pressure. The window varies by agent, but the principle is to avoid concurrent use.

Fourth, there must be no contraindication such as a suspected right ventricular infarct. In RV infarct, the right ventricle depends on preload to maintain output; nitrates reduce preload and can precipitate severe hypotension and reduced cardiac output.

Putting it together, before giving nitroglycerin for chest pain you confirm ischemic-type pain, ensure SBP is at least 100, verify there has been no recent PDE-5 inhibitor use, and rule out conditions like suspected RV infarct that would make nitrates unsafe.