Relaxes vascular smooth muscle – predominantly a venodilator; also produces coronary and systemic arterial vasodilation to a lesser extent.
NTG releases nitric oxide in vascular endothelial cells. Nitric oxide is a gas, which when released in vascular smooth muscle, results in the formation of cyclic guanosine monophosphate (Cyclic GMP). c-GMP relaxes vascular smooth muscle by inactivating myosin light-chain kinase or by stimulating dephosphorelation of myosin phosphate.
For infusion: Nitro is generally mixed in a bottle. IV bags are made of polyvinylchloride (PVC) which absorbs the drug and decreases the concentration.
In hospital, cardiac ischemic chest pain that does not respond to NTG SL and morphine IV is treated with a NTG infusion (typical mix: 50 mg in 250 cc - started at 10-20 µg/min and titrated in 10 µg/min increments to relieve pain).