Nitroglycerin Infusion Protocol
Initial Dosing and Titration
- The American College of Cardiology recommends starting intravenous nitroglycerin at 10 mcg/min and titrating upward by 10 mcg/min every 3-5 minutes until symptom relief or blood pressure response occurs, with a typical maximum of 200 mcg/min 1, 2
- Increase by 10 mcg/min increments every 3-5 minutes until clinical response is observed, and if no response at 20 mcg/min, escalate to 10 mcg/min increments, then 20 mcg/min increments for subsequent increases 1, 2
Maximum Dosing and Contraindications
- The American Heart Association suggests that the commonly used ceiling is 200 mcg/min, though this is not an absolute upper limit, and doses of 300-400 mcg/min have been used safely for prolonged periods without increasing methemoglobin levels 1, 2, 3
- The American College of Cardiology states that if doses exceed 200 mcg/min are needed, consider alternative vasodilator therapy 4
Blood Pressure Parameters
- The American Heart Association recommends not reducing systolic BP below 110 mmHg in previously normotensive patients, and in hypertensive patients, do not reduce mean arterial pressure by more than 25% from baseline 1, 2
- Avoid nitroglycerin entirely if initial systolic BP is <90 mmHg or >30 mmHg below baseline 1, 2, 3
Critical Contraindications and Precautions
- The American College of Cardiology states that there is an absolute contraindication for use of sildenafil within 24 hours or tadalafil/vardenafil within 48 hours due to risk of profound hypotension and death 1, 2, 3
- Use with extreme caution or avoid in suspected right ventricular infarction, and avoid in patients with marked bradycardia or tachycardia 1, 2, 3, 4
Tolerance Management
- Tolerance develops in 7-8 hours and is dose and duration dependent, and typically becomes clinically significant after 24 hours of continuous therapy 1, 2, 3
- If tolerance develops, the infusion rate can be increased, but effectiveness usually returns after 12 hours off nitroglycerin 4