Vasodilator (Nitric Oxide Donor) Pregnancy: Pregnancy Category C. Crosses the placenta; fetal cyanide levels are dose-related to maternal levels. Should be given to a pregnant woman only if clearly needed.

Sodium Nitroprusside

Brand names: Nipride

Sodium nitroprusside is a rapidly acting intravenous vasodilator used in intensive and perioperative settings for hypertensive emergencies and controlled hypotension.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 0.3 mcg/kg/min initial IV infusion, titrated to effect

Route: Intravenous infusion (via volumetric infusion pump)

Frequency: Continuous IV infusion

Max: 10 mcg/kg/min

For blood-pressure reduction (hypertensive emergencies) and acute congestive heart failure. Dilute 50 mg in 250-1000 mL sterile 5% dextrose and protect from light; use only an infusion pump. Average effective rate is about 3 mcg/kg/min. Start at 0.3 mcg/kg/min and titrate upward every few minutes; confirm drug effect after an additional 5 minutes before titrating higher, up to the maximum recommended rate of 10 mcg/kg/min. Continuous blood-pressure monitoring is mandatory (preferably intra-arterial). Cyanide toxicity: giving more than 500 mcg/kg faster than 2 mcg/kg/min generates cyanide faster than the patient can eliminate it. Use special caution in the elderly (greater sensitivity to hypotension). The same weight-based infusion rate (0.3-10 mcg/kg/min) applies to paediatric patients; the rate may be lower than tabulated for patients less than 10 kg - verify against a children's formulary.

Dose adjustments

Renal

Patients with impaired renal function will predictably develop thiocyanate toxicity after prolonged, rapid infusions - monitor and limit exposure.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Compensatory hypertension (e.g. aortic coarctation or arteriovenous shunting)
To produce controlled hypotension during surgery in patients with known inadequate cerebral circulation, or in moribund patients (ASA Class 5E) for emergency surgery
Congenital (Leber's) optic atrophy or tobacco amblyopia
Acute congestive heart failure associated with reduced peripheral vascular resistance (e.g. high-output failure in endotoxic sepsis)

Side effects

Excessive hypotension
Cyanide toxicity (with high or prolonged infusion rates)
Methaemoglobinaemia (rare; after large cumulative doses)
Thiocyanate toxicity (especially with renal impairment or prolonged, rapid infusion)

Interactions

Hypotensive effect augmented by other hypotensive drugs, including ganglionic blocking agents, negative inotropic agents, and inhaled anaesthetics

Clinical monograph

How it works

It releases nitric oxide, which raises intracellular cyclic GMP in vascular smooth muscle to cause balanced arterial and venous dilatation, reducing both preload and afterload; its breakdown generates cyanide that is metabolised to thiocyanate.

Prescribing in practice

Prolonged or high-rate infusion risks cyanide and thiocyanate accumulation and toxicity, so infusions should be kept as short and as low as effective, with caution in hepatic or renal impairment, and the solution must be protected from light.
It can cause profound, rapid hypotension and reflex tachycardia, requiring continuous arterial blood-pressure monitoring, usually intra-arterial.
Avoid abrupt cessation after prolonged use because of rebound hypertension; consult the SPC for preparation and administration.

Monitoring

Monitor blood pressure continuously (ideally intra-arterial), and watch for metabolic acidosis and other features of cyanide or thiocyanate toxicity, particularly with prolonged infusion or organ impairment.

Counselling the patient

Explain that this medicine is given as a closely monitored drip in critical-care or theatre settings.
Inform the team to protect the infusion from light and to watch for signs of toxicity with prolonged use.

Evidence & guidelines

Sodium nitroprusside is a long-established agent for hypertensive emergencies and controlled hypotension; refer to current prescribing references.

Reference: ESC Hypertension Guidelines 2023; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways