NIPRIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NIPRIDE (NIPRIDE).
Nipride (sodium nitroprusside) is a potent vasodilator that acts directly on vascular smooth muscle, both arterial and venous, by releasing nitric oxide (NO). Nitric oxide activates guanylate cyclase, increasing cyclic GMP levels, leading to relaxation of smooth muscle and subsequent reduction in peripheral vascular resistance and blood pressure.
| Metabolism | Sodium nitroprusside is metabolized rapidly in the blood by interaction with hemoglobin to produce cyanide and nitric oxide. Cyanide is further metabolized in the liver by the enzyme rhodanese to thiocyanate, which is eliminated renally. Cyanide may also be converted to cyanmethemoglobin in red blood cells. |
| Excretion | Renal: ~50% as unchanged drug; hepatic metabolism to thiocyanate, which is renally eliminated (half-life 2-3 days); <1% fecal. |
| Half-life | Nitroprusside: ~2 minutes (converted to cyanide); cyanide (as thiocyanate): 2.7 days; clinical context: continuous IV infusion required; thiocyanate accumulation risk in renal impairment. |
| Protein binding | Nitroprusside: <10% bound (non-specific); thiocyanate: ~60% bound to albumin. |
| Volume of Distribution | Nitroprusside: 0.2-0.5 L/kg (small, confined to intravascular space); cyanide: 0.2-0.5 L/kg. |
| Bioavailability | IV: 100% (only route). |
| Onset of Action | IV: 30-60 seconds; maximum effect within 2 minutes. |
| Duration of Action | 1-10 minutes after infusion cessation; clinical note: rapid offset allows precise titration. |
Intravenous infusion: initial 0.3-0.5 mcg/kg/min, titrate up to 10 mcg/kg/min as needed.
| Dosage form | INJECTABLE |
| Renal impairment | No adjustment required for GFR, but monitor for cyanide/thiocyanate toxicity in severe renal impairment (CrCl <30 mL/min). |
| Liver impairment | Use with caution; no specific dose adjustment provided. Avoid in severe hepatic impairment due to risk of thiocyanate and cyanide accumulation. |
| Pediatric use | Intravenous infusion: initial 0.5-1 mcg/kg/min, titrate to effect. Maximum 8 mcg/kg/min. |
| Geriatric use | Start at lower end of dosing range (0.3 mcg/kg/min) due to increased sensitivity and risk of hypotension. Titrate slowly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NIPRIDE (NIPRIDE).
| Breastfeeding | Breastfeeding safety: No human data; nitroprusside and its metabolites (thiocyanate) may be excreted in milk. M/P ratio unknown. Avoid breastfeeding during infusion; consult healthcare provider. |
| Teratogenic Risk | Pregnancy category C. First trimester: Limited human data; animal studies show fetal toxicity at high doses. Second and third trimesters: Risk of fetal cyanide toxicity from nitroprusside metabolism. Use only if maternal benefit outweighs risk. |
| Fetal Monitoring |
■ FDA Black Box Warning
WARNING: Nipride can cause severe hypotension, cyanide toxicity, and thiocyanate toxicity. Prolonged infusion (especially >24 hours) or higher doses may lead to cyanide accumulation, metabolic acidosis, and death. Monitor blood pressure, acid-base status, and cyanide/thiocyanate levels. Have amyl nitrite, sodium nitrite, and sodium thiosulfate available for cyanide antidote.
| Serious Effects |
["Compensatory hypertension (e.g., aortic coarctation, arteriovenous shunt)","Patients with known insufficient blood flow (e.g., severe anemia, hypovolemia)","Leber's optic atrophy or tobacco amblyopia (due to risk of cyanide toxicity)","Congenital (hereditary) optic atrophy","Severe renal impairment (relative contraindication due to thiocyanate accumulation)"]
| Precautions | ["Severe hypotension: Monitor blood pressure continuously; risk of myocardial ischemia, stroke, or renal failure.","Cyanide toxicity: Higher risk with prolonged infusion (>24 hours), hepatic impairment, or doses >10 mcg/kg/min; signs include metabolic acidosis, confusion, seizures.","Thiocyanate toxicity: Accumulates with renal impairment; symptoms include tinnitus, blurred vision, altered mental status.","Methemoglobinemia: Rare, but can occur due to nitric oxide formation; treat with methylene blue if needed."] |
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| Continuous maternal blood pressure monitoring; fetal heart rate monitoring during infusion; maternal cyanide levels if prolonged use ( > 3-4 hours); thiocyanate levels if renal impairment; acid-base status and oxygen saturation. |
| Fertility Effects | No human data on fertility. Animal studies: no adverse effects on fertility at therapeutic doses. |