Nipruss (Sodium Nitroprusside Dihydrate)

Sodium nitroprusside is a direct vasodilator used to manage severe elevations in systemic vascular resistance.

• Hypertensive emergencies: provides rapid, controlled reduction of arterial pressure to prevent end‑organ damage.
• Controlled hypotension during surgery: enables deliberate lowering of blood pressure to improve surgical field visibility.
• Acute heart failure with severe hypertension: reduces afterload and preload, facilitating cardiac output improvement.

• Sodium nitroprusside releases nitric oxide (NO) upon metabolism in the bloodstream. NO activates soluble guanylate cyclase in vascular smooth‑muscle cells, increasing cyclic GMP levels, which leads to relaxation of arterial and venous smooth muscle. The effect is dose‑dependent and reversible, allowing clinicians to titrate infusion rates to achieve target hemodynamic goals while maintaining organ perfusion.

Sodium nitroprusside may be associated with a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Headache: mild to moderate headache occurring during infusion.
• Nausea: transient nausea or vomiting.
• Flushing: sensation of warmth and skin reddening.
• Hypotension: excessive fall in blood pressure if infusion rate is too high.

Serious or Rare Side Effects

• Cyanide toxicity: accumulation of cyanide leading to metabolic acidosis and neurologic symptoms.
• Thiocyanate accumulation: can cause tinnitus, confusion, or renal dysfunction with prolonged use.
• Methemoglobinemia: elevated methemoglobin levels impairing oxygen delivery.

When using sodium nitroprusside, clinicians should observe specific precautions to minimize risks and ensure safe administration.

• Monitoring: continuous arterial blood pressure monitoring is required throughout the infusion.
• Dose titration: adjust infusion rate gradually based on real‑time hemodynamic response.
• Cyanide risk: limit duration of therapy and consider antidotes in patients with renal impairment.
• Laboratory checks: regularly assess serum cyanide, thiocyanate, and methemoglobin levels during prolonged use.
• Store at ambient temperature: keep the solution below 25 °C, protected from light, in the original container.

Sodium nitroprusside can interact with other agents, altering its efficacy or increasing toxicity.

Major Interactions (Avoid)

• Sodium nitrite: concurrent use may exacerbate methemoglobinemia.
• MAO inhibitors: can potentiate hypertensive crises when nitroprusside is withdrawn abruptly.
• Other vasodilators: additive hypotensive effect may lead to severe blood pressure drops.

Moderate Interactions (Monitor Closely)

• Diuretics: may enhance hypotensive response, requiring careful dose adjustment.
• ACE inhibitors or ARBs: combined effect on vascular tone may increase risk of profound hypotension.
• Anticonvulsants (e.g., phenytoin): may affect cyanide metabolism, necessitating monitoring.