ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
Direct Vasodilator (NO Donor) — Hypertensive Emergency / Aortic Dissection Pregnancy: Avoid — fetal cyanide toxicity reported; use only if other agents have failed in life-threatening emergency

Sodium Nitroprusside

Brand names: Nitropress, Nipride

Adult dose

Dose: 0.3–0.5 micrograms/kg/min IV initially; titrate to response
Route: Intravenous infusion (protect from light — use opaque cover)
Frequency: Continuous infusion
Max: 8–10 micrograms/kg/min (short-term); reduce if cyanide toxicity suspected; max 3 micrograms/kg/min if >3 hours
Balanced arterial and venous dilation — reduces preload and afterload. Solution must be protected from light (photodegradation releases cyanide). Reconstitute in 5% dextrose. Cyanide accumulates at high doses/prolonged use/renal failure — monitor for toxicity. Use lowest effective dose for shortest duration. Antidote: hydroxocobalamin IV or sodium thiosulphate.

Paediatric dose

Dose: 0.3–0.5 micrograms/kg/min initially mcg/min/kg
Route: IV infusion
Frequency: Continuous
Max: 8 micrograms/kg/min (short-term only)
Used in paediatric hypertensive emergencies under PICU specialist guidance

Dose adjustments

Renal

Avoid prolonged use in renal impairment — thiocyanate (cyanide metabolite) accumulates; monitor thiocyanate levels

Hepatic

Use with caution — some hepatic metabolism

Paediatric weight-based calculator

Used in paediatric hypertensive emergencies under PICU specialist guidance

Clinical pearls

  • Antidote for cyanide toxicity: hydroxocobalamin (Cyanokit) 5 g IV — chelates cyanide directly; preferred over sodium thiosulphate in hemodynamically unstable patients
  • Aortic dissection: target SBP 100–120 mmHg; use with IV beta-blocker (esmolol/labetalol) — nitroprusside alone increases dP/dt (aortic wall shear force) which is harmful in dissection
  • Light protection mandatory — infusion bag and tubing must be wrapped in opaque material; degradation produces cyanide
  • Thiocyanate accumulates in renal failure — toxic level >100 mcg/mL (normal <10); dialysable
  • Extremely short half-life (minutes) — effect ceases almost immediately on stopping infusion; provides excellent minute-to-minute BP control in ICU

Contraindications

  • Compensatory hypertension (AV shunts, coarctation)
  • Leber's optic atrophy
  • Tobacco amblyopia
  • Vitamin B12 deficiency
  • Inadequate cerebral circulation

Side effects

  • Hypotension (most common — titrate carefully)
  • Cyanide toxicity (tachycardia, metabolic acidosis, altered consciousness, smell of bitter almonds)
  • Thiocyanate toxicity (tinnitus, blurred vision, delirium, seizures — with prolonged use)
  • Reflex tachycardia
  • Nausea
  • Headache
  • Methaemoglobinaemia

Interactions

  • Antihypertensives — additive profound hypotension
  • Sildenafil/PDE5 inhibitors — absolute contraindication (severe hypotension)
  • Other NO donors/nitrates — additive

Monitoring

  • Continuous arterial line BP monitoring mandatory
  • Acid-base status (lactataemia indicates cyanide toxicity)
  • Thiocyanate levels (prolonged use/renal impairment)
  • Methaemoglobin levels
  • Cyanide levels if toxicity suspected

Reference: BNFc; BNF 90; ESC Aortic Disease Guidelines 2014; AHA/ACC Hypertensive Crisis Guidelines; MHRA SPC Nitropress. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Pathways