In management of discomfort/pain of suspected cardiac origin, at what systolic blood pressure may you assist with self-administered prescribed NTG?

• A. SBP ≥ 90 mmHg
• B. SBP ≥ 110 mmHg
• C. SBP ≥ 120 mmHg
• D. SBP ≥ 100 mmHg

Answer: (D)

Nitroglycerin aids relief of ischemic chest pain by dilating vessels, which lowers preload and afterload and can improve myocardial oxygen supply-demand. But it can also cause a drop in blood pressure, so you only assist with a self-administered prescribed dose when there’s enough perfusion pressure to tolerate it. The threshold used in typical EMS practice is a systolic blood pressure of 100 mmHg or higher. At or above this level, the patient can usually tolerate the vasodilating effect without risking dangerous hypotension. If the systolic pressure is below 100 mmHg, you should withhold NTG and continue other treatments per protocol. Also verify the patient has a prescribed NTG and watch for contraindications such as recent use of nitrates with PDE-5 inhibitors.