Recommended NTG Infusion Rates for Acute Coronary Syndrome and Severe Hypertension
For acute coronary syndrome, intravenous nitroglycerin should be initiated at 5 mcg/min with incremental increases of 5 mcg/min every 3-5 minutes until clinical response, with a typical range of 5-200 mcg/min. 1, 2
Nitroglycerin Infusion Protocol for Acute Coronary Syndrome
- Starting dose: 5 mcg/min using a non-absorbing infusion set 2
- Titration: Increase by 5 mcg/min every 3-5 minutes until response is noted 2
- Adjustment strategy:
- If no response at 20 mcg/min, increase by 10 mcg/min
- Once partial response is observed, reduce increment size and increase interval between adjustments
- Typical effective range: 5-200 mcg/min 1
- Maximum concentration: Should not exceed 400 mcg/mL 2
Nitroglycerin Infusion Protocol for Severe Hypertension/Hypertensive Emergency
- Dosage range: 5-200 mcg/min 1
- Titration: Increase by 5 mcg/min every 5 minutes until target blood pressure is achieved 1
- Duration of action: 3-5 minutes (requires continuous infusion) 1
Monitoring Parameters
- Continuous monitoring of blood pressure and heart rate is essential for all patients 2
- Additional monitoring of pulmonary capillary wedge pressure may be appropriate in selected patients 2
- Maintain adequate systemic blood pressure and coronary perfusion pressure 2
Clinical Considerations
Efficacy
- High-dose NTG (≥100 μg/min) may achieve blood pressure targets faster than low-dose regimens (<100 μg/min) in acute pulmonary edema 3
- For acute pulmonary edema, the American Heart Association recommends starting at 5 mcg/min with increments of 5 mcg/min every 3-5 minutes 4
Tolerance Development
- Continuous NTG infusion can lead to tolerance within 24 hours 5
- Significant attenuation of hemodynamic effects may occur after 8-12 hours of continuous infusion 5
Contraindications and Precautions
- Avoid NTG in patients who have used:
- Sildenafil within the previous 24 hours
- Tadalafil within the previous 48 hours 1
- Use with caution in patients with:
- Systolic BP <90 mmHg or 30 mmHg below baseline
- Right ventricular infarction
- Severe aortic stenosis 4
Special Situations
- For patients with myocardial ischemia, consider additional beta-blockade if tachycardia develops 1
- In acute pulmonary edema, both nitroglycerin and sodium nitroprusside are effective, with nitroprusside being preferred for optimizing preload and afterload 1
Practical Administration Tips
- When changing concentration, flush or replace the infusion set to ensure accurate dosing 2
- Non-absorbing tubing requires lower doses than PVC administration sets 2
- Hypersensitive patients (e.g., angina without other complications) may respond fully to doses as small as 5 mcg/min 2
Nitroglycerin's efficacy in reducing preload and afterload makes it valuable for both acute coronary syndrome and hypertensive emergencies, but careful titration and monitoring are essential to maximize benefits while minimizing adverse effects.