Nitropress (nitroprusside sodium)
Last reviewed · Source: First Databank (FDB) drug data
Overview
Sodium nitroprusside is a vasodilating and hypotensive agent.
Sodium nitroprusside is a potent direct arterial and venous dilator. Sodium nitroprusside exhibits more venous than arterial activity, although it has less selectivity than nitroglycerin. When sodium nitroprusside is administered by IV infusion to hypertensive or normotensive patients, slight increases in heart rate and a variable effect on cardiac output are observed with decreased blood pressure.
Moderate doses of sodium nitroprusside in hypertensive patients produce renal vasodilation without an appreciable increase in renal blood flow or a decrease in glomerular filtration.
The hypotensive action of sodium nitroprusside results from peripheral vasodilation caused by a direct action on vascular smooth muscle. No relaxation of other smooth muscle tissue, such as the uterus or duodenum, has been demonstrated. The drug's venous dilatory effect promotes peripheral pooling of the blood and reduces venous cardiac return, which decreases left ventricular end diastolic pressure and pulmonary capillary wedge pressure (preload).
Arteriolar relaxation reduces systemic vascular resistance, systolic arterial pressure, mean arterial pressure (afterload), and dilates the coronary arteries.
IV infusion of sodium nitroprusside produces hypotensive effects within 1-2 minutes of initiation. Blood pressure begins to rise immediately when the infusion is slowed or stopped and returns to pretreatment levels within 1-10 minutes. Sodium nitroprusside is rapidly distributed into the extracellular fluid compartment.
Animal studies have shown that nitroprusside passes the placental barrier. Thiocyanate, a metabolite of sodium nitroprusside, has also been shown to distribute into human milk.
Sodium nitroprusside is cleared by a reaction with hemoglobin in erythrocytes to form cyanmethemoglobin and cyanide. Cyanogen (cyanide radical) is produced, which is converted to thiocyanate in the liver by the enzyme thiosulfate sulfurtransferase (rhodanase). This mitochondrial enzyme normally is present in excess quantities such that the rate-limiting factor in the conversion of cyanogen to thiocyanate usually is the availability of sulfur donors (e.g., thiosulfate, cystine, cysteine).
Physiologic thiocyanate serum levels normally range from 3-15 mcg/mL. Physiologic conversion of cyanide to thiocyanate at steady-state generally occurs at about 1 mcg/kg per minute; conversion capacity is exceeded with sodium nitroprusside infusions of slightly above 2 mcg/kg per minute, resulting in the accumulation of cyanide. Mild neurotoxicity (tinnitus, miosis, hyperreflexia) begins to appear at serum thiocyanate concentrations of 60 mcg/mL; fatalities have been reported at concentrations of 200 mcg/mL.
The circulatory half-life of sodium nitroprusside is approximately 2 minutes.
Most of the cyanide produced during sodium nitroprusside metabolism is excreted in the form of thiocyanate. Cyanide not otherwise removed binds to cytochromes. Thiocyanate excretion is primarily renal.
The elimination half-life of thiocyanate is 3 days when renal function is normal, but is doubled or tripled in patients with renal failure.
Generic name: nitroprusside sodium
Reference product & biosimilars
No reference, biosimilar or interchangeable associated with this drug.
Today’s intelligence on Nitropress
Indications
The following indications are listed for Nitropress:
- Acute Decompensated Heart Failure
- Controlled Hypotension
- Hypertensive Crisis
Also known as: Acute Heart Failure, Controlled Decreased Blood Pressure, Overt Cardiac Failure, Overt Chf, Overt Congestive Heart Failure, Overt Heart Failure, Uncontrolled Cardiac Failure.
Dosing
No dosing information is available for this tab.
Sodium nitroprusside is administered by IV infusion only using a controlled-infusion device (i.e., infusion pump); IV infusion devices regulated only by gravity or mechanical clamps should not be used. The rate of administration should be adjusted to maintain the desired hypotensive effect, as determined by continuous monitoring of blood pressure, using either a continually reinflated sphygmomanometer or, preferably, an intra-arterial pressure sensor. The drug should be administered for no longer than 10 minutes at the maximum infusion rate (i.e., 10 mcg/kg per minute). When titrating sodium nitroprusside infusion, blood pressure should be assessed for at least 5 minutes before further titrating the infusion rate.
Sodium nitroprusside is commercially available prediluted in 0.9% sodium chloride injection (0.5 mg/mL and 0.2 mg/mL concentrations) and as an injection concentrate (25 mg/mL). Commercially available sodium nitroprusside injection concentrate (25 mg/mL) must be further diluted prior to IV infusion. The contents of one vial of injection concentrate containing 50 mg of the drug should be diluted in 250-1000 mL of 5% dextrose injection. Vials of the drug are for single use only. Nitroprusside solutions prepared using the injection concentrate should be protected from light by promptly wrapping the containers in the supplied opaque sleeve, aluminum foil, or other opaque material; it is not necessary to cover the infusion drip chamber or IV tubing. If properly protected from light, diluted solutions of the drug are stable for 24 hours. The infusion solution has a clear colorless to red/brown color; if it is blue, green, or bright red, it should not be used. No other drug should be added to the infusion fluid for simultaneous administration with sodium nitroprusside.
Sodium nitroprusside vials should be stored protected from light in their carton until use at 20-25degreesC.
No dosing information is available for this tab.
No dosing information is available for this tab.
Drug interactions
There is no enhanced messaging for this drug.
There are no contraindication interactions for this drug.
There are no severe interactions for this drug.
There are no moderate interactions for this drug.
Contraindications
*Sodium nitroprusside should not be used in the treatment of compensatory hypertension (e.g., arteriovenous shunt, coarctation of the aorta).
*The use of sodium nitroprusside to produce controlled hypotension during surgery is contraindicated in patients with inadequate cerebral circulation and is not intended for use during emergency surgery in patients near death (American Society of Anesthesiologists (ASA) class 5E).
*Use of the drug is contraindicated in patients with congenital (Leber's) optic atrophy or tobacco amblyopia; these conditions, although rare, are associated with absent or deficient thiosulfate sulfurtransferase (rhodanase), and these patients have unusually high cyanogen to thiocyanate ratios.
*Sodium nitroprusside is contraindicated in patients with acute heart failure associated with reduced peripheral vascular resistance, such as high-output heart failure that may accompany endotoxic sepsis.
*Concomitant use of sodium nitroprusside and phosphodiesterase (PDE) type 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil) or soluble guanylate cyclase stimulators (e.g., riociguat) is contraindicated.
There are no contraindication contraindications for this drug.
There are no severe contraindications for this drug.
There are no moderate contraindications for this drug.
Adverse reactions
Adverse effects resulting from IV administration of sodium nitroprusside are uncommon and are usually associated with a too-rapid reduction in blood pressure. Excessive hypotension and cyanide toxicity are the most common.
There are no severe adverse reactions for this drug.
There are no less severe adverse reactions for this drug.
Precautions
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Efficacy of sodium nitroprusside in pediatric patients has been established based on adult trials and supported by 2 studies in pediatric patients: a parallel, dose-ranging study and a long-term infusion study in which sodium nitroprusside dosage was titrated according to blood pressure. The primary efficacy variable in these studies was mean arterial pressure (MAP). The patients were <17 years of age; at least 50% of the patients were prepubertal, and about 50% of prepubertal patients were <2 years of age, including 4 neonates. Both studies demonstrated the blood pressure-lowering effect of sodium nitroprusside. In the latter study, sodium nitroprusside reduced MAP below that of placebo control for at least 12 hours. Similar effects on MAP were observed in all age groups in these studies, and no novel safety issues were noted.
Based on animal findings and its mechanism of action, sodium nitroprusside may lead to cyanide exposure and adverse effects on the fetus. Available postmarketing data in pregnant women are insufficient to establish a drug-associated risk of adverse pregnancy outcomes with sodium nitroprusside. Studies in pregnant sheep have shown that sodium nitroprusside crosses the placenta and effects were dose-related.
Prolonged use and higher dosages of sodium nitroprusside during pregnancy can result in cyanide toxicity, which may be fatal to a developing fetus. In the unusual situation that there is no alternative therapy to sodium nitroprusside, pregnant women should be informed of the potential fetal risk.
There are no data on the presence of sodium nitroprusside in human milk, the effects on the breast-fed infant, or the effects on milk production; however, thiocyanate, a metabolite of sodium nitroprusside, is present in human milk. It is unclear if and for how long thiocyanate levels in milk are clinically relevant.
The manufacturer states that special caution should be used with sodium nitroprusside in geriatric patients, as they may be more sensitive to the hypotensive effects of the drug.
Geriatric patients may be more sensitive to the hypotensive effects of sodium nitroprusside, therefore caution should be exerted with use in this patient population.
ICD codes
No ICD codes are available for this drug.
Formulary status
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Last reviewed · Source: First Databank (FDB) drug data
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