sodium nitroprusside in 0.9% sodium chloride

1 INDICATIONS AND USAGE Sodium nitroprusside is a direct acting vasodilator indicated for: Immediate reduction of blood pressure ( 1.1 ) Producing controlled hypotension to reduce bleeding during surgery ( 1.2 ) Treatment of acute heart failure to reduce left ventricular end-diastolic pressure, pulmonary capillary wedge pressure, peripheral vascular resistance and mean arterial blood pressure ( 1.3 ) 1.1 Immediate Reduction of Blood Pressure Sodium nitroprusside is indicated for the immediate reduction of blood pressure of adult and pediatric patients in hypertensive crises. 1.2 Induction and Maintenance of Controlled Hypotension Sodium nitroprusside indicated for induction and maintenance of controlled hypotension in adults and children during surgery, to reduce bleeding. 1.3 Treatment of Acute Heart Failure Sodium nitroprusside is indicated for the treatment of acute heart failure to reduce left ventricular end-diastolic pressure, pulmonary capillary wedge pressure, peripheral vascular resistance and mean arterial blood pressure.

2 DOSAGE AND ADMINISTRATION Initiate infusion of sodium nitroprusside at a rate of 0.3 mcg/kg/min, and titrate every few minutes until the desired effect is achieved OR the maximum recommended infusion rate of 10 mcg/kg/min has been reached ( 2.2 ). 2.1 Inspection Inspect parenteral drug products for particulate matter and discoloration prior to administration, whenever solution and container permit. Sodium nitroprusside should be a clear colorless to red/brown color; do not use if solution is blue, green, or bright red. Dosing Continuously monitor blood pressure in patients receiving sodium nitroprusside. Start infusion of sodium nitroprusside at a rate of 0.3 mcg/kg/min. Evaluate blood pressure for at least 5 minutes before titrating to a higher or lower dose to achieve the desired blood pressure. The dose may be titrated upward until: the desired effect is achieved, systemic blood pressure cannot be further reduced without compromising the perfusion of vital organs, or the maximum recommended infusion rate of 10 mcg/kg/min has been reached, whichever occurs first. In patients with eGFR <30 mL/min/1.73 m 2 , limit the mean infusion rate to less than 3 mcg/kg/min. In anuric patients, limit the mean infusion rate to 1 mcg/kg/min. 2.3 Administration Do not administer other drugs in the same solution with sodium nitroprusside. Sodium nitroprusside must be delivered by a volumetric infusion pump because small variations in infusion rate can lead to wide, undesirable variations in blood pressure [see Clinical Pharmacology ( 12.2 )].

3 DOSAGE FORMS AND STRENGTHS Injection: 50 mg/100 mL of 0.9% sodium chloride (0.5 mg/mL), 20 mg/100 mL of 0.9% sodium chloride (0.2 mg/mL), and 10 mg/50 mL of 0.9% sodium chloride (0.2 mg/mL). Sodium Nitroprusside in 0.9% Sodium Chloride Injection, ready to use is supplied as a sterile, unpreserved, colorless to red-brown solution available in a single-dose vial. Injection: 50 mg of sodium nitroprusside in 100 mL of 0.9% sodium chloride (0.5 mg/mL) in 100 mL single-dose vials, 20 mg of sodium nitroprusside in 100 mL of 0.9% sodium chloride (0.2 mg/mL) in 100 mL single-dose vials and 10 mg of sodium nitroprusside in 50 mL of 0.9% sodium chloride (0.2 mg/mL) in 50 mL single-dose vials ( 3 ).

4 CONTRAINDICATIONS Diseases with compensatory hypertension (e.g., coarctation of the aorta, arteriovenous shunting). 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. Acute heart failure associated with reduced peripheral vascular resistance. Concomitant use with sildenafil, tadalafil, vardenafil, or riociguat. Diseases with compensatory hypertension (e.g. coarctation of the aorta, arteriovenous shunting) ( 4 ). Inadequate cerebral circulation or moribund patients (A.S.A. Class 5E) coming to emergency surgery ( 4 ). Congenital (Leber’s) optic atrophy or tobacco amblyopia ( 4 ). Acute heart failure with reduced peripheral vascular resistance ( 4 ). Concomitant use with sildenafil, tadalafil, vardenafil, or riociguat ( 4 ).

6 ADVERSE REACTIONS The following adverse reactions are described, or described in greater detail, in other sections: Hypotension [see Warnings and Precautions ( 5.1 )] Cyanide Toxicity [see Warnings and Precautions ( 5.2 )] Thiocyanate Toxicity [see Warnings and Precautions ( 5.3 )] Methemoglobinemia [see Warnings and Precautions ( 5.4 )] Increased Intracranial Pressure [see Warnings and Precautions ( 5.5 )] Anemia and Hypovolemia [see Warnings and Precautions ( 5.6 )] Less common adverse reactions include: Cardiovascular: Bradycardia, electrocardiographic changes, tachycardia, palpitations, retrosternal discomfort Dermatologic: Rash Endocrine: Hypothyroidism Gastrointestinal: Ileus, nausea, abdominal pain Hematologic: Decreased platelet aggregation Musculoskeletal: Muscle twitching Neurologic: Increased intracranial pressure, dizziness, headache Miscellaneous: Flushing, diaphoresis, venous streaking, irritation at the infusion site Most common adverse reactions are hypotension and cyanide toxicity ( 6 ). To report SUSPECTED ADVERSE REACTIONS, contact Slate Run Pharmaceuticals, LLC at 1-888-341-9214 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

8 USE IN SPECIFIC POPULATIONS 8.1 Pregnancy Risk Summary Based on animal data and mechanism of action, sodium nitroprusside may lead to cyanide exposure and potential adverse effects in the fetus [see Clinical Pharmacology ( 12.3 ) and Clinical Considerations ] . Published post-marketing reports with sodium nitroprusside use in pregnant women are insufficient to inform a drug-associated risk of adverse pregnancy related outcomes [see Data ] . There were no animal reproduction studies conducted with sodium nitroprusside during pregnancy. However, there are published studies in pregnant sheep that demonstrate that nitroprusside crosses the placenta and that fetal cyanide levels were dose-related to maternal levels of sodium nitroprusside [see Data]. Advise pregnant women of the potential risk to a fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions Prolonged use and large doses of sodium nitroprusside during pregnancy may result in cyanide toxicity that may be fatal to the fetus. In the unusual case that there is no appropriate alternative to therapy with sodium nitroprusside for a particular patient, apprise the mother of the potential risk to the fetus [see Warnings and Precautions ( 5.2 )] . Data Human Data A small number of cases have reported adverse events, including stillbirths, in pregnant women with severe pregnancy-induced hypertension who were treated with sodium nitroprusside. However, methodological limitations, including small sample size and limited information on sodium nitroprusside dosage and duration of treatment, as well as the cyanide concentration in maternal blood or fetal tissue, preclude a reliable evaluation of the potential risk of adverse fetal outcomes with the use of sodium nitroprusside during pregnancy. Animal Data In three studies in pregnant ewes, nitroprusside was shown to cross the placental barrier. Fetal cyanide levels were shown to be dose-related to maternal levels of nitroprusside. The metabolic transformation of sodium nitroprusside given to pregnant ewes led to fatal levels of cyanide in the fetuses. The infusion of 25 mcg/kg/min of sodium nitroprusside for one hour in pregnant ewes resulted in the death of all fetuses. Pregnant ewes infused with 1 mcg/kg/min of sodium nitroprusside for one hour delivered normal lambs. 8.2 Lactation Risk Summary There is no information about the presence of sodium nitroprusside in human milk, the effects on the breastfed infant, or the effects on milk production. Thiocyanate, one of sodium nitroprusside’s metabolites, is present in human milk. It is unclear how long, if ever, levels of thiocyanate in milk are clinically relevant. 8.4 Pediatric Use Efficacy in the pediatric population was established based on adult trials and supported by the dose-ranging trial (Study 1) and an open label trial of at least 12 hour infusion at a rate that achieved adequate MAP control (Study 2) with pediatric patients on sodium nitroprusside. No novel safety issues were seen in these studies in pediatric patients [see Clinical Studies ( 14 )].

12.1 Mechanism of Action Sodium nitroprusside interacts with oxyhemoglobin to produce methemoglobin, cyanide, and nitric oxide (NO). NO then reacts with guanylate cyclase in vascular smooth muscle to produce cGMP that reduces intracellular calcium concentrations resulting in 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.

11 DESCRIPTION Sodium nitroprusside is disodium pentacyanonitrosylferrate (2-) dihydrate, a hypotensive agent whose structural formula is Sodium Nitroprusside has a molecular formula Na 2 [Fe(CN) 5 NO] • 2H 2 O and molecular weight of 297.95. Dry sodium nitroprusside is a reddish-brown powder, soluble in water. Sodium nitroprusside solution is rapidly degraded by trace contaminants, often with resulting color changes [see Dosage and Administration ( 2.1 )]. Sodium Nitroprusside in 0.9% Sodium Chloride Injection, ready to use is supplied as a sterile, unpreserved, colorless to red-brown solution packaged in a single-dose 100-mL vial. Each 100 mL of solution in vial contains 50 mg of sodium nitroprusside (0.5 mg/mL), 900 mg of sodium chloride, USP (9 mg/mL), in sterile water for injection, USP. Sodium Nitroprusside in 0.9% Sodium Chloride Injection, ready to use is also supplied as a sterile, unpreserved, colorless to red-brown solution packaged in a single-dose 100-mL vial. Each 100 mL of solution in vial contains 20 mg of sodium nitroprusside (0.2 mg/mL), 900 mg of sodium chloride, USP (9 mg/mL), in sterile water for injection, USP. Sodium Nitroprusside in 0.9% Sodium Chloride Injection, ready to use is also supplied as a sterile, unpreserved, colorless to red-brown solution packaged in a single-dose 50-mL vial. Each 50 mL of solution in vial contains 10 mg of sodium nitroprusside (0.2 mg/mL), 450 mg of sodium chloride, USP (9 mg/mL), in sterile water for injection, USP. chemical structure

10 OVERDOSAGE Overdosage of nitroprusside can be manifested as excessive hypotension or cyanide toxicity [see Warnings and Precaution ( 5.1 , 5.2 )] or as thiocyanate toxicity [see Warnings and Precautions ( 5.3 )] . Cyanide toxicity causes venous hyperoxemia with bright red venous blood. Cells become unable to extract the oxygen delivered to them, leading to air hunger, confusion and death. Lactic acidosis may occur, but its emergence may lag other life-threatening manifestations of cyanide toxicity. Cyanide levels can be measured by many laboratories, and blood-gas studies that can detect venous hyperoxemia or acidosis are widely available. Acidosis may not appear until more than an hour after the appearance of dangerous cyanide levels. Suspicion of cyanide toxicity is adequate grounds for initiation of treatment. Treatment of cyanide toxicity consists of: discontinuing sodium nitroprusside; administration of sodium nitrite to convert as much hemoglobin into methemoglobin as the patient can safely tolerate; and then infusing sodium thiosulfate to convert the cyanide into thiocyanate Hemodialysis is ineffective in removal of cyanide, but it will eliminate most thiocyanate. Sodium nitrite is available in a 3% solution, and 4-6 mg/kg (about 0.2 mL/kg) should be injected over 2-4 minutes. This dose can be expected to convert about 10% of the patient’s hemoglobin into methemoglobin; this level of methemoglobinemia is not associated with any important hazard of its own. Immediately after infusion of the sodium nitrite, sodium thiosulfate should be infused. This agent is available in 10% and 25% solutions, and the recommended dose is 150-200 mg/kg; a typical adult dose is 50 mL of the 25% solution. Thiosulfate treatment of an acutely cyanide-toxic patient will raise thiocyanate levels, but not to a dangerous degree. The nitrite/thiosulfate regimen may be repeated, at half the original doses, after two hours. Cyanide antidote kits are available.

16 HOW SUPPLIED/STORAGE AND HANDLING Sodium Nitroprusside in 0.9% Sodium Chloride Injection, ready to use is supplied in amber-colored, single-dose, 50 mg/100 mL (0.5 mg/mL) Fliptop Vials (NDC 70436-207-80), 20 mg/100 mL (0.2 mg/mL) Fliptop Vials (NDC 70436-206-80) and 10 mg/50 mL (0.2 mg/mL) Fliptop Vials (NDC 70436-205-80). Store at 20° to 25°C (68° to 77°F). [See USP Controlled Room Temperature]. To protect Sodium Nitroprusside in 0.9% Sodium Chloride Injection, ready to use from light, vial should be stored in its carton until used.