Nitroprusside sodium

Nitroprusside (also sodium nitroprusside or nitroprusside sodium) is an inorganic compound with the molecular formula: Na2[Fe(CN)5NO] - 2 H2O, which belongs to NO-donors (nitrovasodilators) and to the cyanides. It lowers the tonus of resistance and capacitance vessels equally. As a result, the blood pressure and the pre- and post-load of the heart decrease. In contrast to other representatives of this substance class (GTN, ISMN, ISDN), it conveys its effect - like molsidomine, by the way - by a non-enzymatic route, which is why no nitrate typical tolerance development is to be expected with nitroprusside sodium and moslidomine.

Because of its complete inactivation in the gastrointestinal tract, nitroprusside sodium can only be administered intravenously. It is eliminated from the plasma with a half-life of 3-4min. Cyanide and NO are formed during the breakdown in the smooth muscle. An enzyme of the liver (rhodanase) and exogenous thiosulphate, which is endogenous or administered with therapeutic intent, ensure cyanide detoxification to thiocyanate. Thiocynate is then detoxified.

Hypertensive crises, controlled hypotension during surgery.

Nitroprusside should not be used during pregnancy and lactation

Occasionally, considerable drops in blood pressure can occur due to the effect on venous and arterial vascular muscles, which is why an invasive, arterial blood pressure measurement during and after the administration of Nitroprusside is recommended.

Due to the release of cyanides when used over longer periods of time, the administration of sodium thiosulphate is necessary in such cases for appropriate detoxification.

Sodium nitroprusside should be used with caution in combination with other antihypertensive drugs (e.g. vasodilators such as nitrates, beta-receptor blockers, calcium antagonists, other antihypertensive or tricyclic antidepressants and neuroleptics) as their antihypertensive effect can be enhanced.

Due to a possible contrary effect of nitric oxide donors, such as ergot alkaloids, simultaneous application should be avoided.

Nitroprusside should not be used for:

• Aortic coarctation
• Liver optic atrophy
• Tobacco amblyopia
• vitamin B12 deficiency
• metabolic acidosis
• Hypothyroidism
• intrapulmonary arteriovenous shunts

• Nitroprusside should not be used during pregnancy and lactation

Nitroprusside is available again in Germany under the trade name Nipruss® since May 2017.

Sodium nitroprusside is an active substance from the family of nitrovasodilators, a group of drugs that are broken down in the smooth muscle of the vessels of the large and small circulation and the draining urinary and biliary tracts, thereby releasing NO (NO donors). Nitroprusside sodium is not suitable for long-term therapy.

All therapeutically applied nitrovasodilators unfold their antiischemic effectiveness uniformly via the same mechanism. They release radical NO, albeit via different bioactivation pathways. NO has the greatest relaxation effect where there is the greatest lack of physiological NO.

1. Graefe KH et al Pharma with effects on the vascular system In: Graefe KH et al (Eds) Pharmacology and Toxicology. Georg Thieme Publisher Stuttgart S.177-181
2. Speeches J (1990) Molsidomine. Blood Vessels 27:282-294