Nitroprusside
NITROPRESS
What it isDirect nitric oxide donor dilating arteries and veins; hypertensive emergency and acute afterload reduction.
Why this oneOnset and offset within seconds give finer control than any other agent.
What limits it⚑ Cyanide toxicity presents with unexplained acidosis; limit exposure and monitor closely. Protect the infusion from light.
FDA label
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| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| BP reduction / hypertension (IV infusion) | Adults and pediatric patients | 0.3 mcg/kg/min IV infusion (pump required) | Average effective rate ~3 mcg/kg/min IV; usual range 0.5–10 mcg/kg/min | 10 mcg/kg/min IV (never >10 min at max rate) |
| Acute congestive heart failure | Adults and pediatric patients | 0.3 mcg/kg/min IV, titrate guided by invasive hemodynamic monitoring with urine output | Titrate until cardiac output no longer increases, BP cannot be lowered further without compromising perfusion, or max rate reached | 10 mcg/kg/min IV |
Titration Titrate upward every few minutes; confirm drug effect at any rate for an additional 5 minutes before increasing.
Renal Prolonged infusion: do not exceed 3 mcg/kg/min (anuric patients: 1 mcg/kg/min) to keep thiocyanate <1 mmol/L; measure thiocyanate daily if faster
Hepatic Undefined
Cyanide accumulates when infusion >2 mcg/kg/min or total >500 mcg/kg given faster than 2 mcg/kg/min; infusion at 10 mcg/kg/min must never last >10 min.
Instructions
- Dilute 50 mg in 250–1000 mL sterile D5W; not suitable for direct injection
- Protect diluted solution from light (opaque sleeve/foil); stable 24 h if protected
- Do not use discolored (blue/green/bright red) or particulate-containing solutions
- No other drugs in the same solution; do not use flexible container in series connections
- Infuse only via infusion pump (preferably volumetric), never gravity/mechanical clamps
- Continuous BP monitoring required (continually reinflated cuff or intra-arterial sensor)
- Use special caution in elderly (more sensitive to hypotensive effect)
- Sodium thiosulfate co-infusion (5–10× nitroprusside rate) can reduce cyanide hazard but may potentiate hypotension and cause thiocyanate toxicity/hypovolemia
Contraindications
- Compensatory hypertension (aortic coarctation, arteriovenous shunting)
- Induced hypotension during surgery in patients with inadequate cerebral circulation, or moribund (A.S.A. Class 5E) patients in emergency surgery
- Congenital (Leber's) optic atrophy or tobacco amblyopia (defective/absent rhodanase — high cyanide/thiocyanate ratios)
- Acute CHF with reduced peripheral vascular resistance (e.g., high-output failure of endotoxic sepsis)
Cautions
- Excessive hypotension → irreversible ischemic injury or death without continuous monitoring
- Cyanide toxicity (potentially lethal) except at brief/low (<2 mcg/kg/min) rates; lab tests give imperfect guidance
- Methemoglobinemia in patients receiving >10 mg/kg (treat with methylene blue 1–2 mg/kg IV, cautiously)
- Thiocyanate toxicity with prolonged/rapid infusion, especially in renal impairment (neurotoxic at 60 mg/L; life-threatening at 200 mg/L); interferes with thyroid iodine uptake
- Elderly patients more sensitive to hypotensive effects
Adverse reactions
- Too-rapid BP reduction: abdominal pain, apprehension, diaphoresis, dizziness, headache, muscle twitching, nausea, palpitations, restlessness, retching, retrosternal discomfort (resolve on slowing infusion)
- Bradycardia, tachycardia, ECG changes
- Increased intracranial pressure
- Methemoglobinemia; thiocyanate toxicity
- Rash; hypothyroidism; ileus; decreased platelet aggregation
- Flushing, venous streaking, infusion-site irritation
Pregnancy Undefined
Lactation Undefined
⚠ BOXED WARNINGS
- Cyanide toxicity
- Precipitous blood pressure decreases
Classes and tags
Clinical profile
Mechanism of action: Nitroprusside ballicule
