What is the dose of nitroglycerin (NTG) infusion?

From the Guidelines

Nitroglycerin infusion should be initiated at a rate of 10 mcg per min and increased by 10 mcg per min every 3 to 5 min until some relief of symptoms or blood pressure response is noted, as recommended by the most recent guidelines 1. The dose of nitroglycerin infusion can be adjusted based on patient response, with most patients responding to doses between 50-200 mcg/minute.

• The maximum recommended dose is generally 200 mcg/minute, though some patients may require higher doses in certain clinical situations.
• The infusion should be administered using a glass bottle and non-PVC tubing with an infusion pump for accurate dosing.
• Common dilutions include 50 mg in 250 mL (200 mcg/mL) or 50 mg in 500 mL (100 mcg/mL) of D5W or normal saline.
• Blood pressure and heart rate should be monitored continuously during administration, with dose adjustments made to maintain systolic blood pressure above 90-100 mmHg.
• Nitroglycerin works by relaxing vascular smooth muscle through nitric oxide release, causing vasodilation that reduces preload and afterload, decreasing myocardial oxygen demand and improving coronary blood flow.
• Tolerance may develop within 24-48 hours of continuous infusion, potentially requiring dose increases to maintain the therapeutic effect, as noted in the guidelines 1. The guidelines also recommend that intravenous NTG should be avoided in patients with initial systolic blood pressure less than 90 mm Hg or 30 mm Hg or more below baseline or with marked bradycardia or tachycardia 1. It is also important to note that the combination of intravenous nitroglycerin with a beta-adrenergic blocker in appropriate patients is well tolerated and theoretically attractive because the risk of undesired tachycardia may be reduced, as mentioned in the guidelines 1.

From the FDA Drug Label

DOSAGE & ADMINISTRATION ... Although the usual starting adult dose range reported in clinical studies was 25 mcg/min or more, these studies used PVC administration sets. THE USE OF NON-ABSORBING TUBING WILL RESULT IN THE NEED FOR REDUCED DOSES. If a peristaltic action infusion pump is used, an appropriate administration set should be selected with a drip chamber that delivers approximately 60 microdrops/mL ... When using a non-absorbing infusion set, the initial dosage should be 5 mcg/min delivered through an infusion pump capable of exact and constant delivery of the drug. Subsequent titration must be adjusted to the clinical situation, with dose increments becoming more cautious as partial response is seen Initial titration should be in 5 mcg/min increments, with increases every 3-5 minutes until some response is noted. The dose of nitroglycerine infusion should be titrated to the desired level of hemodynamic function, with a usual starting adult dose range of 25 mcg/min or more when using PVC administration sets, or an initial dosage of 5 mcg/min when using a non-absorbing infusion set 2.

• The dose may need to be reduced when using non-absorbing tubing.
• Incremental doses of 5 mcg/min should be used, with increases every 3-5 minutes until some response is noted.
• Careful titration and monitoring are required, especially in patients who may be hypersensitive to the effects of nitroglycerin.

From the Research

Nitroglycerine Infusion Dose

• The dose of nitroglycerine infusion is not explicitly stated in the provided studies 3, 4, 5, 6, 7.
• However, the studies discuss the use of nitroglycerine in various clinical settings, including acute coronary syndromes, heart failure, and pulmonary edema 3, 4, 6, 7.
• The mechanism of action of nitroglycerine involves the release of nitric oxide, leading to venodilation and arteriodilation, which can help reduce preload and afterload 3, 5.
• The studies suggest that nitroglycerine can be effective in improving clinical outcomes, such as reducing mortality and improving hemodynamic measurements, in patients with cardiovascular disease 4, 6, 7.
• However, the optimal dose and administration protocol for nitroglycerine infusion are not clearly defined in the provided studies, and further research is needed to determine the best approach for using this medication in clinical practice 3, 4, 5, 6, 7.

Clinical Considerations

• Nitroglycerine is often administered intravenously in the emergency department, which allows for titration to effect with predictable pharmacokinetics 3.
• The use of nitroglycerine in prehospital settings has been associated with improved clinical outcomes, including reduced mortality, in patients with suspected acute coronary syndrome 4.
• The antiplatelet effects of nitrates, including nitroglycerine, may also contribute to their clinical benefits in patients with cardiovascular disease 5.

Future Research Directions

• Further studies are needed to determine the optimal dose and administration protocol for nitroglycerine infusion in various clinical settings 3, 4, 5, 6, 7.
• Large-scale clinical trials are required to provide evidence-based answers on the use of nitroglycerine in clinical practice 5, 7.