Neophyr (Nitric Oxide)

Neophyr (inhaled nitric oxide) is used in conditions involving elevated pulmonary vascular resistance.

• Persistent pulmonary hypertension of the newborn (PPHN): reduces pulmonary artery pressure and improves oxygenation in affected neonates.
• Acute pulmonary hypertension in adults: provides selective pulmonary vasodilation to support hemodynamics during critical care.
• Right ventricular failure secondary to pulmonary hypertension: decreases right ventricular afterload and may improve cardiac output.

• Inhaled nitric oxide diffuses into pulmonary vascular smooth‑muscle cells where it binds to the heme moiety of soluble guanylate cyclase. This activation raises intracellular cyclic GMP levels, leading to smooth‑muscle relaxation and selective vasodilation of the pulmonary vasculature without significant systemic effects.

Inhaled nitric oxide may be associated with several adverse reactions, ranging from mild to serious.

Common Side Effects

• Headache
• Flushing
• Nausea
• Dizziness
• Cough
• Mild methemoglobinemia

Serious or Rare Side Effects

• Severe methemoglobinemia
• Rebound pulmonary hypertension after abrupt discontinuation
• Systemic hypotension
• Increased bleeding tendency due to platelet inhibition
• Toxic nitrogen dioxide formation from gas degradation
• Acute respiratory distress

Neophyr should be used with careful clinical monitoring and adherence to safety guidelines.

• Dose titration: adjust inhaled concentration under clinical supervision.
• Monitoring: regularly assess methemoglobin levels during therapy.
• Avoid abrupt discontinuation: taper to prevent rebound pulmonary hypertension.
• Use with caution in patients with hemolytic disease or severe anemia.
• Contraindication: known hypersensitivity to nitric oxide or its delivery system.
• Store at ambient temperature: keep cylinder in original container, protect from heat and direct sunlight.

Nitric oxide can interact with other agents that affect vascular tone or hemoglobin.

Major Interactions (Avoid)

• Phosphodiesterase‑5 inhibitors (e.g., sildenafil): additive vasodilation may cause severe hypotension.
• Inhaled anesthetics such as nitrous oxide: may increase formation of nitrogen dioxide, a toxic by‑product.
• Anticoagulants: heightened bleeding risk due to platelet inhibition.

Moderate Interactions (Monitor Closely)

• Inhaled bronchodilators: may enhance pulmonary vasodilatory effects.
• Systemic vasodilators (e.g., nitroglycerin): monitor blood pressure for additive hypotension.
• Certain antibiotics (e.g., sulfonamides) that predispose to methemoglobinemia.