Nitroprusside

Name

• Nitroprusside.

Class of drug

• Antihypertensive.

Uses

Action

• An antihypertensive drug    that causes peripheral vasodilation (arterial and venous)    directly, independent of the autonomic innervation.
• Lowers systemic and pulmonary vascular resistance and systemic arterial blood pressure   →   increasing cardiac output and reducing ventricular filling pressure.

Indications

• Short term management of severe systemic hypertensive crises.
• Treatment of acute life-threatening heart failure secondary to mitral or aortic regurgitation.
• Management of severe refractory congestive heart failure, often in combination with dopamine    .

Adverse reactions

Effects of overdosage

• Excessive doses, prolonged therapy, depletion of hepatic thiosulfate supply may lead to cyanide or thiocyanate toxicity.
• Thiocyanate toxicity may cause delirium in dogs.

Other reported reactions

• Profound hypotension (excessive doses, prolonged therapy, depletion of hepatic thiosulfate supply).

Investigation of adverse reaction

• Monitor acid/base status to evaluate therapy and to detect metabolic acidosis (early sign of cyanide toxicity).
• Monitor serum thiocyanate levels in patients on prolonged therapy if possible, especially those with concurrent renal dysfunction.

Treatment

• Administer Vitamin B12 parenterally as this may prevent cyanide toxicity.