Nitric oxide

Nitric oxide

Clinical data
Uses	Pulmonary HTN; RHF
Contraindications	severe LHF; R to L shunt
Routes of administration	Inhalational
Dosage	1-20 ppm (parts per million)
Pharmacodynamics
Pharmacokinetics
Physical and chemical data
Article quality
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Nitric oxide (NO) is a naturally occurring endothelial-derived vasodilator that exhibits most of its vasodilatory effects in the pulmonary vasculature. It is frequently indicated for patients with right heart failure and hypoxemia. It exists as a colorless odorless gas, and is administered inhalationally.

Uses

• Pulmonary HTN
• Right ventricular failure

Contraindications

Absolute contraindications

• Severe left heart dysfunction
• Congenital heart conditions with dependent right to left shunt (e.g. interrupted aortic arch, critical aortic stenosis, hypoplastic left heart syndrome), which would shunt blood away from systemic circulation toward pulmonary circulation

Pharmacology

Pharmacodynamics

Mechanism of action

Nitric oxide diffuses to smooth muscle of pulmonary vasculature -> activates soluble guanylate cyclase (sGC) -> converts GTP to cGMP -> activates protein kinase G -> increases Ca2+ reuptake -> decreased calcium decreasing myosin phosphorylation -> relaxation of smooth muscle.

History

Initially discovered in 1987. Won Nobel Prize in Physiology and Medicine in 1998.