Mechanism
How Nitric Oxide works
Diffuses into pulmonary vascular smooth muscle and activates guanylate cyclase, increasing cGMP and causing selective pulmonary vasodilation.
← Respiratory Pharmacology
PVDNBRC High Yield5/5 Importance
Nitric Oxide Respiratory Pharmacology Guide
Class, mechanism, indications, adverse effects, kinetics, exam traps, and NBRC-style study pearls.
Nitric oxide is an inhaled pulmonary vasodilator used most classically for persistent pulmonary hypertension of the newborn and selected cases of refractory hypoxemia with pulmonary hypertension physiology. It improves ventilation-perfusion matching by selectively dilating pulmonary vessels in ventilated lung units. Key monitoring concerns include methemoglobinemia, nitrogen dioxide toxicity, and rebound pulmonary hypertension if discontinued abruptly.
Clinical Pearl
What to remember
Never stop iNO abruptly; rebound pulmonary hypertension is a classic board-style safety issue.
Kinetics
Onset, peak, and duration
1
Onset
Minutes
2
Peak
Rapid
3
Duration
Only while continuously delivered
Quick facts
- Subclass
- Inhaled pulmonary vasodilator
- NBRC importance
- 5/5
- Difficulty
- 4/5
- Brands
- iNO, INOmax
Common indications
- Persistent pulmonary hypertension of the newborn
- Severe hypoxemic respiratory failure with pulmonary hypertension physiology
- Rescue therapy for refractory hypoxemia in selected ICU patients
Adverse effects
- Methemoglobinemia
- Nitrogen dioxide toxicity
- Rebound pulmonary hypertension
- Hypotension
- Worsening oxygenation if withdrawn abruptly
Contraindications
- Hypersensitivity to formulation components
Cautions and safety issues
- Monitor methemoglobin levels
- Monitor nitrogen dioxide levels
- Avoid abrupt discontinuation due to rebound pulmonary hypertension
- Use caution with left ventricular dysfunction
NBRC-style question
NBRC-style pharmacology review
A patient scenario involves neonate with persistent pulmonary hypertension. Which medication concept should the respiratory therapy student recognize?
High-yield answer
iNO = pulmonary vasodilation, watch metHb
Interactive practice
Practice in PharmaGenius
Master this medication through adaptive review of class, mechanism, indications, adverse effects, exam traps, and clinical scenarios. Missed concepts can later be surfaced for targeted remediation.
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Common Exam Traps
These are the answer choices, mechanisms, or medication classes most commonly confused with this medication on RT school and NBRC-style exams.
- Bronchodilator
- Mucolytic
- Inhaled corticosteroid
- Surfactant replacement
- Beta agonist
High-Yield Clinical Scenarios
- Neonate with persistent pulmonary hypertension
- Refractory hypoxemia with pulmonary hypertension
- Question about methemoglobinemia monitoring
- Question about rebound pulmonary hypertension after abrupt discontinuation
Related study paths
Continue building pharmacology mastery
Use this medication page as a reference, then reinforce it with interactive practice and related PulmTools study resources.