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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.
DOSAGE AND ADMINISTRATION
Dilution to Proper Strength for Infusion
Depending on the desired concentration, the solution containing 50 mg of NITROPRESS must be further diluted in 250-1000 mL of sterile 5% dextrose injection. The diluted solution should be protected from light, using the supplied opaque sleeve, aluminum foil, or other opaque material. It is not necessary to cover the infusion drip chamber or the tubing.
Verification of The Chemical Integrity of The Product
Sodium nitroprusside solution can be inactivated by reactions with trace contaminants. The products of these reactions are often blue, green, or red, much brighter than the faint brownish color of unreacted NITROPRESS. Discolored solutions, or solutions in which particulate matter is visible, should not be used. If properly protected from light, the freshly diluted solution is stable for 24 hours.
No other drugs should be administered in the same solution with sodium nitroprus side.
Avoidance of Excessive Hypotension
While the average effective rate in adult and pediatric patients is about 3 mcg/kg/min, some patients will become dangerously hypotensive when they receive NITROPRESS at this rate. Infusion of sodium nitroprusside should therefore be started at a very low rate (0.3 mcg/kg/min), with upward titration every few minutes until the desired effect is achieved or the maximum recommended infusion rate (10 mcg/kg/min) has been reached.
Because sodium nitroprusside's hypotensive effect is very rapid in onset and in dissipation, small variations in infusion rate can lead to wide, undesirable variations in blood pressure. Since there is inherent variation in blood pressure measurement, confirm the drug effect at any infusion rate after an additional 5 minutes before titrating to a higher dose to achieve the desired blood pressure. Sodium nitroprus side should not be infused through ordinary I.V. apparatus , regulated only by gravity and mechanical clamps . Only an infusion pump, preferably a volumetric pump, should be used.
Because sodium nitroprusside can induce essentially unlimited blood-pressure reduction, the blood pressure of a patient receiving this drug must be continuously monitored, using either a continually reinflated sphygmomanometer or (preferably) an intra-arterial pressure sensor. Special caution should be used in elderly patients, since they may be more sensitive to the hypotensive effects of the drug.
When sodium nitroprusside is used in the treatment of acute congestive heart failure, titration of the infusion rate must be guided by the results of invasive hemodynamic monitoring with simultaneous monitoring of urine output. Sodium nitroprusside can be titrated by increasing the infusion rate until:
- measured cardiac output is no longer increasing,
- systemic blood pressure cannot be further reduced without compromising the perfusion of vital organs, or
- the maximum recommended infusion rate has been reached, whichever comes earliest. Specific hemodynamic goals must be tailored to the clinical situation, but improvements in cardiac output and left ventricular filling pressure must not be purchased at the price of undue hypotension and consequent hypoperfusion.
Table 2 below shows the infusion rates corresponding to the recommended initial and maximal doses (0.3 mcg/kg/min and 10 mcg/kg/min, respectively) for both adult and pediatric patients of various weights. This infusion rate may be lower than indicated in the table for patients less than 10 kg. Note that when the concentration used in a given patient is changed, the tubing is still filled with a solution at the previous concentration.
Table 2: Infusion Rates (mL/hour) to Achieve Initial
(0.3 mcg/kg/min) and Maximal (10 mcg/kg/min) Dosing of NITROPRESS
|Volume NITROPRESS concentration||250 mL 50 mg 200 mcg/mL||500 mL 50 mg 100 mcg/mL||1000 mL 50 mg 50 mcg/mL|
Avoidance Of Cyanide Toxicity
As described in CLINICAL PHARMACOLOGY above, when more than 500 mcg/kg of sodium nitroprusside is administered faster than 2 mcg/kg/min, cyanide is generated faster than the unaided patient can eliminate it. Administration of sodium thiosulfate has been shown to increase the rate of cyanide processing, reducing the hazard of cyanide toxicity. Although toxic reactions to sodium thiosulfate have not been reported, the co-infusion regimen has not been extensively studied, and it cannot be recommended without reservation. In one study, sodium thiosulfate appeared to potentiate the hypotensive effects of sodium nitroprusside.
Co-infusions of sodium thiosulfate have been administered at rates of 5-10 times that of sodium nitroprusside. Care must be taken to avoid the indiscriminate use of prolonged or high doses of sodium nitroprusside with sodium thiosulfate as this may result in thiocyanate toxicity and hypovolemia. Incautious administration of sodium nitroprusside must still be avoided, and all of the precautions concerning sodium nitroprusside administration must still be observed.
Consideration of Methemoglobinemia and Thiocyanate Toxicity
Rare patients receiving more than 10 mg/kg of sodium nitroprusside will develop methemoglobinemia; other patients, especially those with impaired renal function, will predictably develop thiocyanate toxicity after prolonged, rapid infusions. In accordance with the descriptions in ADVERSE REACTIONS above, patients with suggestive findings should be tested for these toxicities.
WARNING: Do not use flexible container in series connections.
NITROPRESS (sodium nitroprusside injection) is supplied in amber-colored, single-dose 50 mg/2 mL Fliptop Vials (NDC 0409-3024-01).
Store at 20 to 25°C (68 to 77°F). [See USP Controlled Room Temperature.]
To protect NITROPRESS from light, it should be stored in its carton until it is used.
Hospira, Inc., Lake Forest, IL 60045 USA. Revised: Dec 2013This monograph has been modified to include the generic and brand name in many instances.
Last reviewed on RxList: 2/10/2016
Additional Nitropress Information
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