What is nitric oxide gas and how is it used?
Inomax is a vasodilator indicated to improve oxygenation and reduce the need for extracorporeal membrane oxygenation in term and near-term (>34 weeks gestation) neonates with hypoxic respiratory failure associated with clinical or echocardiographic evidence of pulmonary hypertension in conjunction with ventilatory support and other appropriate agents.
What are the side effects of nitric oxide gas?
Rebound Pulmonary Hypertension Syndrome following Abrupt Discontinuation
Wean from Inomax. Abrupt discontinuation of Inomax may lead to worsening oxygenation and increasing pulmonary artery pressure, i.e., Rebound Pulmonary Hypertension Syndrome. Signs and symptoms of Rebound Pulmonary Hypertension Syndrome include:
If Rebound Pulmonary Hypertension occurs, reinstate Inomax therapy immediately.
Hypoxemia from Methemoglobinemia
Nitric oxide combines with hemoglobin to form methemoglobin, which does not transport oxygen. Methemoglobin levels increase with the dose of Inomax; it can take 8 hours or more before steady-state methemoglobin levels are attained. Monitor methemoglobin and adjust the dose of Inomax to optimize oxygenation. If methemoglobin levels do not resolve with decrease in dose or discontinuation of Inomax, additional therapy may be warranted to treat methemoglobinemia.
Airway Injury from Nitrogen Dioxide
Nitrogen dioxide (NO2) forms in gas mixtures containing NO and O2. Nitrogen dioxide may cause airway inflammation and damage to lung tissues. If there is an unexpected change in NO2 concentration, or if the NO2 concentration reaches 3 ppm when measured in the breathing circuit, then the delivery system should be assessed in accordance with the Nitric Oxide Delivery System O&M Manual troubleshooting section, and the NO2 analyzer should be recalibrated. The dose of Inomax and/or FiO2 should be adjusted as appropriate.
Worsening Heart Failure
Patients with left ventricular dysfunction treated with Inomax may experience pulmonary edema, increased pulmonary capillary wedge pressure, worsening of left ventricular dysfunction, systemic hypotension, bradycardia and cardiac arrest. Discontinue Inomax while providing symptomatic care. The most common adverse reaction is hypotension.
What is the dosage for nitric oxide gas?
Inomax (nitric oxide) gas is available in an 800 ppm concentration.
The recommended dose is 20 ppm, maintained for up to 14 days or until the underlying oxygen desaturation has resolved.
Doses greater than 20 ppm are not recommended.
- Use only with an Inomax DSIR operated by trained personnel
- Avoid abrupt discontinuation.
What drugs interact with nitric oxide gas?
Nitric oxide donor compounds may increase the risk of developing methemoglobinemia.
Is nitric oxide gas safe to use while pregnant or breastfeeding?
Animal reproduction studies have not been conducted with Inomax. It is not known if Inomax can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. Inomax is not indicated for use in adults.
Medically Reviewed on 6/11/2019
All content for this nitric oxide gas monograph courtesy of the U.S. Food and Drug Administration