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Nitroprusside Nitropress ® - Renal dosing

Usual Dosing (Adults)

Initial: 0.3-0.5 mcg/kg/minute IV - increase in increments of 0.5 mcg/kg/minute, titrating to the desired hemodynamic effect or the appearance of headache or nausea. Usual dose: 3 mcg/kg/minute - rarely need >4 mcg/kg/minute. Max: 10 mcg/kg/minute. Do not use the maximum dose for more than 10 minutes.


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 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 nitroprusside.

Avoidance of excessive hypotension: While the average effective rate in adults and children 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. Sodium nitroprusside 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.

The table 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 adults and children of various weights. Some of the listed infusion rates are so slow or so rapid as to be impractical, and these practicalities must be considered when the concentration to be used is selected. Note that when the concentration used in a given patient is changed, the tubing is still filled with a solution at the previous concentration.

Avoidance of cyanide toxicity: As described in the package insert - CLINICAL PHARMACOLOGY section, 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.

Infusion Rates (mL/hour) to Achieve Initial (0.3 mcg/kg/min) and

Maximal (10 mcg/kg/min) Dosing of NITROPRESS
Volume   250 mL   500 mL     1000 mL
NITROPRESS   50 mg   50 mg     50 mg
concentration   200 mcg/mL 100 mcg/mL   50 mcg/mL
pt weight              
kg lbs   init max   init max     init max  
10 22   1 30   2 60     4 120  
20 44   2 60   4 120     7 240  
30 66   3 90   5 180     11 360  
40 88   4 120   7 240     14 480  
50 110   5 150   9 300     18 600  
60 132   5 180   11 360     22 720  
70 154   6 210   13 420     25 840  
80 176   7 240   14 480     29 960  
90 198   8 270   16 540     32 1080  
100 220   9 300   18 600     36 1200

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 the package insert ADVERSE REACTIONS section, patients with suggestive findings should be tested for these toxicities.

WARNING: Do not use flexible container in series connections.

Renal Dosing

dialysis Renal impairment:  LIMIT USE (use briefly or not at all) - accumulation of thiocyanate may occur.  Use the lowest end of the dosage range with renal impairment (<2 mcg /kg /minute). Thiocyanate toxicity occurs in patients with renal impairment or those on prolonged infusions. 

Monitor for cyanide and thiocyanate toxicity. Signs of toxicity include: venous hypoxemia, acidosis, mental status changes, and death. Thiocyanate levels >60 mg/L are mildly neurotoxic and can become life-threatening at approximately 200 mg/L.

Consider fenoldopam in patients with renal insufficiency (alternative to nitroprusside) - lacks cyanide / thiocyanate toxicity.

Hemodialysis

dialysis Avoid use.

Reference(s)

National Institutes of Health, U.S. National Library of Medicine, DailyMed Database.
Provides access to the latest drug monographs submitted to the Food and Drug Administration (FDA). Please review the latest applicable package insert for additional information and possible updates.  A local search option of this data can be found here.

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The authors make no claims of the accuracy of the information contained herein; and these suggested doses are not a substitute for clinical judgment. Neither GlobalRPh Inc. nor any other party involved in the preparation of this program shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.PLEASE READ THE DISCLAIMER CAREFULLY BEFORE ACCESSING OR USING THIS SITE. BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER.   Read the disclaimer
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