displayName: DESCRIPTION SECTION
FDA Article Code: 34089-3
Sodium nitroprusside is disodium pentacyanonitrosylferrate(2-) dihydrate, a hypotensive agent whose structural formula is:
Sodium Nitroprusside, whose molecular formula is Na2[Fe(CN)5NO] • 2H2O, and whose molecular weight is 297.95. Dry sodium nitroprusside is a reddish-brown powder, soluble in water. In an aqueous solution infused intravenously, sodium nitroprusside is a rapid-acting vasodilator, active on both arteries and veins.
Sodium nitroprusside solution is rapidly degraded by trace contaminants, often with resulting color changes. (See
DOSAGE AND ADMINISTRATION
section.) The solution is also sensitive to certain wavelengths of light, and it must be protected from light in clinical use.
Sodium Nitroprusside Injection is available as:
50 mg Fliptop Vial – Each 2 mL vial contains the equivalent of 50 mg sodium nitroprusside dihydrate in sterile water for injection.
displayName: CLINICAL PHARMACOLOGY SECTION
FDA Article Code: 34090-1
The principal pharmacological action of sodium nitroprusside is relaxation of vascular smooth muscle and consequent dilatation of peripheral arteries and veins. Other smooth muscle (e.g., uterus, duodenum) is not affected. Sodium nitroprusside is more active on veins than on arteries, but this selectivity is much less marked than that of nitroglycerin. Dilatation of the veins promotes peripheral pooling of blood and decreases venous return to the heart, thereby reducing left ventricular end diastolic pressure and pulmonary capillary wedge pressure (preload). Arteriolar relaxation reduces systemic vascular resistance, systolic arterial pressure, and mean arterial pressure (afterload). Dilatation of the coronary arteries also occurs.
In association with the decrease in blood pressure, sodium nitroprusside administered intravenously to hypertensive and normotensive patients produces slight increases in heart rate and a variable effect on cardiac output. In hypertensive patients, moderate doses induce renal vasodilatation roughly proportional to the decrease in systemic blood pressure, so there is no appreciable change in renal blood flow or glomerular filtration rate.
In normotensive subjects, acute reduction of mean arterial pressure to 60 to 75 mm Hg by infusion of sodium nitroprusside caused a significant increase in renin activity. In the same study, ten renovascular-hypertensive patients given sodium nitroprusside had significant increases in renin release from the involved kidney at mean arterial pressures of 90 to 137 mm Hg.
The hypotensive effect of sodium nitroprusside is seen within a minute or two after the start of an adequate infusion, and it dissipates almost as rapidly after an infusion is discontinued. The effect is augmented by ganglionic blocking agents and inhaled anesthetics.
INDICATIONS AND USAGE
displayName: INDICATIONS & USAGE SECTION
FDA Article Code: 34067-9
Sodium nitroprusside is indicated for the immediate reduction of blood pressure of adult and pediatric patients in hypertensive crises. Concomitant longer-acting antihypertensive medication should be administered so that the duration of treatment with sodium nitroprusside can be minimized.
Sodium nitroprusside is also indicated for producing controlled hypotension in order to reduce bleeding during surgery.
Sodium nitroprusside is also indicated for the treatment of acute congestive heart failure.
displayName: CONTRAINDICATIONS SECTION
FDA Article Code: 34070-3
Sodium nitroprusside should not be used in the treatment of compensatory hypertension, where the primary hemodynamic lesion is aortic coarctation or arteriovenous shunting.
Sodium nitroprusside should not be used to produce hypotension during surgery in patients with known inadequate cerebral circulation, or in moribund patients (A.S.A. Class 5E) coming to emergency surgery.
Patients with congenital (Leber’s) optic atrophy or with tobacco amblyopia have unusually high cyanide/thiocyanate ratios. These rare conditions are probably associated with defective or absent rhodanase, and sodium nitroprusside should be avoided in these patients.
Sodium nitroprusside should not be used for the treatment of acute congestive heart failure associated with reduced peripheral vascular resistance such as high-output heart failure that may be seen in endotoxic sepsis.
displayName: WARNINGS SECTION
FDA Article Code: 34071-1
(See also the boxed warning at the beginning of this insert.)
The principal hazards of Sodium Nitroprusside administration are excessive hypotension and excessive accumulation of cyanide (see also
DOSAGE AND ADMINISTRATION
displayName: ADVERSE REACTIONS SECTION
FDA Article Code: 34084-4
The most important adverse reactions to sodium nitroprusside are the avoidable ones of excessive hypotension and cyanide toxicity, described above under
. The adverse reactions described in this section develop less rapidly and, as it happens, less commonly.
displayName: OVERDOSAGE SECTION
FDA Article Code: 34088-5
Overdosage of nitroprusside can be manifested as excessive hypotension or cyanide toxicity (see
) or as thiocyanate toxicity (see
The acute intravenous mean lethal doses (LD50) of nitroprusside in rabbits, dogs, mice, and rats are 2.8, 5.0, 8.4, and 11.2 mg/kg, respectively.
displayName: HOW SUPPLIED SECTION
FDA Article Code: 34069-5
Sodium Nitroprusside Injection is supplied in an amber-colored vial as follows:
Sodium Nitroprusside Injection (25 mg per mL)
||50 mg per 2 mL Single-Dose Vial
||1 vial per carton