# Sodium Nitroprusside: veterinary dose and monograph

> Sodium Nitroprusside is a veterinary cardiovascular drug. A potent, fast-acting BALANCED (arterial AND venous) vasodilator given ONLY as a closely-monitored IV constant-rate infusion (mcg/kg/MINUTE) for HYPERTENSIVE EMERGENCIES and acute, fulminant congestive heart failure / cardiogenic… Indications include hypertensive emergency / crisis — rapid, titratable blood-pressure reduction; acute fulminant congestive heart failure / cardiogenic pulmonary oedema (afterload + preload reduction); controlled hypotension during certain procedures (specialist). This monograph lists 2 reference doses for dogs and cats, each with route, frequency and source.

Source: https://vetmasterji.com/drugs/nitroprusside · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Cardiovascular
- **Also known as:** SNP, Nipride, Sodium nitroprusside
- **Species with doses:** Dogs and Cats
- **Routes:** IV
- **Last reviewed:** 1 October 2026

## Indications

- Hypertensive emergency / crisis — rapid, titratable blood-pressure reduction
- Acute fulminant congestive heart failure / cardiogenic pulmonary oedema (afterload + preload reduction)
- Controlled hypotension during certain procedures (specialist)

## Sodium Nitroprusside dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Dogs

*Sodium Nitroprusside doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Hypertensive crisis / acute CHF (CRI) | 1–10 µg/kg/min | IV | CRI, titrated | — |

- Hypertensive crisis / acute CHF (CRI): Papich 5e: 1–5 µg/kg/min, maximum 10; start at 2 and increase by 1 µg/kg/min until the target pressure is reached. Plumb’s p.897: hypertensive crisis start 1–2 µg/kg/min, titrate every 3–5 min and lower BP by 25% over 4 h; fulminant pulmonary oedema usually 2–5 µg/kg/min (upper limit 8–10) for 12–48 h, often with dobutamine. Keep systolic >90 mmHg; continuous BP monitoring. Protect the solution from light; cyanide toxicity with infusions >3 days.

### Cats

*Sodium Nitroprusside doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Hypertensive crisis / acute CHF (CRI) | 0.5–5 µg/kg/min | IV | CRI, titrated | — |

- Hypertensive crisis / acute CHF (CRI): Plumb’s p.897: start 0.5 µg/kg/min, increasing every 3–5 min to the target (Proulx); pulmonary oedema usually 1–2 µg/kg/min with an upper limit of 2 (Lichtenberger). Papich 5e (dogs and cats): 1–5 µg/kg/min, maximum 10. Cats are more sensitive to oxidative damage — keep total dose minimal; dedicated line, never flush; continuous monitoring.

## Contraindications

Without continuous blood-pressure monitoring / ICU setting. Hypovolaemia, severe hypotension, and compensatory hypertension (e.g. raised ICP, AV shunts). Significant hepatic/renal impairment (cyanide/thiocyanate accumulation). Prolonged/high-dose infusion (cyanide toxicity). Known hypersensitivity.

## Species-specific warnings

> **Caution:** Cats: Use lower infusion rates and meticulous continuous BP monitoring; cats are sensitive to hypotension.

## Adverse effects

- Profound hypotension, reflex tachycardia
- Cyanide / thiocyanate toxicity with prolonged/high-dose use (metabolic acidosis, tachypnoea, mentation change)
- Rebound hypertension if stopped abruptly after prolonged use
- Nausea; methaemoglobinaemia (rare)

## Drug interactions

- Other vasodilators/antihypertensives (incl. PDE5 inhibitors): additive, potentially severe hypotension
- Drugs depleting thiosulphate: increased cyanide toxicity risk
- Negative inotropes/anaesthetics: additive hypotension

## Pregnancy and lactation

Reserve for life-threatening maternal hypertension/CHF; cyanide can cross the placenta — minimise dose/duration.

## Monitoring

- CONTINUOUS blood pressure (ideally invasive/arterial) and heart rate — titrate to target
- Infusion rate/duration and cumulative dose (cyanide risk) — limit high-dose/prolonged use
- Acid–base/lactate (cyanide surveillance); mentation
- Light protection of the infusion; taper to avoid rebound hypertension

## Toxicity and overdose

Two dose-/duration-dependent hazards: (1) profound hypotension (titration-related), and (2) CYANIDE/thiocyanate toxicity — metabolic (lactic) acidosis, tachypnoea, altered mentation, and cardiovascular collapse — especially with high doses (>~10 mcg/kg/min), prolonged infusion (>24–48 h), or hepatic/renal impairment. Methaemoglobinaemia is a rare additional effect.

Management: STOP the infusion (hypotension reverses within minutes). For suspected CYANIDE toxicity: sodium thiosulphate (and hydroxocobalamin) ± sodium nitrite per cyanide-antidote protocols, plus supportive care and correction of acidosis. Support blood pressure (fluids/vasopressor) and ventilation; monitor lactate/acid–base.

## Clinical pearls

- The most titratable vasodilator — instantaneous on/off makes it ideal for hypertensive crises and fulminant CHF, but it DEMANDS continuous BP monitoring (ICU)
- Balanced arterial + venous dilation reduces both afterload and preload
- Mind CYANIDE: keep doses ≤~10 mcg/kg/min, limit duration, and watch for metabolic acidosis — have thiosulphate available
- Protect from light (it degrades), dilute fresh, and taper to avoid rebound hypertension

## Mechanism of action

Nitroprusside spontaneously releases nitric oxide in the bloodstream, activating guanylate cyclase in vascular smooth muscle and raising cyclic GMP, which relaxes BOTH arterial (afterload) and venous (preload) smooth muscle — producing rapid, balanced vasodilation. Its metabolism releases cyanide ions (detoxified to thiocyanate by the liver, requiring thiosulphate/B12 cofactors and renal excretion), which accumulate and become toxic with prolonged or high-dose infusion or organ impairment.

## Formulations and products

- Injection 50 mg vial (reconstitute, dilute for CRI)
- Sodium Nitroprusside (Nipride) — 50 mg vial (reconstitute), Injection (CRI, light-protected) (human-label)

## Storage

Vial: protect from LIGHT (degrades rapidly); reconstitute and dilute fresh, wrap the bag/line in opaque cover, and discard if discoloured (blue/dark). Use within ~24 h.

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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## Frequently asked questions

### What is the dose of Sodium Nitroprusside for dogs?

Reference doses for Sodium Nitroprusside in dogs: 1–10 µg/kg/min IV CRI, titrated (Hypertensive crisis / acute CHF (CRI)). Confirm against the label and the patient before use.

### What is the dose of Sodium Nitroprusside for cats?

Reference doses for Sodium Nitroprusside in cats: 0.5–5 µg/kg/min IV CRI, titrated (Hypertensive crisis / acute CHF (CRI)). Confirm against the label and the patient before use.

### When should Sodium Nitroprusside not be used?

Without continuous blood-pressure monitoring / ICU setting. Hypovolaemia, severe hypotension, and compensatory hypertension (e.g. raised ICP, AV shunts). Significant hepatic/renal impairment (cyanide/thiocyanate accumulation). Prolonged/high-dose infusion (cyanide toxicity). Known hypersensitivity.

### What are the side effects of Sodium Nitroprusside in animals?

Profound hypotension, reflex tachycardia; Cyanide / thiocyanate toxicity with prolonged/high-dose use (metabolic acidosis, tachypnoea, mentation change); Rebound hypertension if stopped abruptly after prolonged use; Nausea; methaemoglobinaemia (rare).

## Sources

- Plumb's Veterinary Drug Handbook
- Merck Veterinary Manual, 11th edition
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.