Sodium nitroprusside pharmacological effects

J.B. Salom, M.D. Barbera, J.M. Centeno, M. Orti, G. Torregrosa and E. Alborch, Relaxant effects of sodium nitroprusside and NONOates in rabbit basilar artery, Pharmacology, 57 (1998) 79-87. 

SODIUM NITROPRUSSIDE Sodium nitroprusside (NITROPRESS) is a prodrug and potent vasodilator that reduces both ventricular filling pressures and systemic vascular resistance. It has a rapid onset (2-5 minutes) and offset (quickly metabolized to cyanide and NO, the active vasodilator) of action and its dose can be titrated expeditiously to achieve the desired hemodynamic effect. For these reasons, nitroprusside is commonly used in intensive-care settings for rapid control of severe hypertension and for the management of decompensated heart failure. The basic pharmacologic properties of this drug are described in Chapter 32. 

When the effect of nitric oxide donors on cGMP-accumulation is studied, one must take into account the rate of NO-release from the donor compound The diffusion rate of NO is quite high, because of the small size and hpophihcity of this molecule (45), Sodium nitroprusside (SNP) is often used an NO-donor. This compound is inexpensive, which is an important asset. However, the byproduct after NO-release, [Fe(CN)5], is not devoid of pharmacological activity (46) In addition, SNP is light sensitive, although in most cases this property should not rule out use of this compound. In 10-min incubations with brain slices, SNP and the NO-donors S-nitroso-acetyl-penicillamine and streptozotocin were equally effective in raising cGMP levels (unpublished). 

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