Above which infusion rate does cyanide toxicity become a concern in a healthy adult receiving sodium nitroprusside?

Above which infusion rate does cyanide toxicity become a concern in a healthy adult receiving sodium nitroprusside?

• A. 0.5 µg/kg/min
• B. 2 µg/kg/min
• C. 10 µg/kg/min
• D. 20 µg/kg/min

Answer: (B)

Sodium nitroprusside releases cyanide as it dilates vessels, and the body can detoxify only a limited cyanide load at a time. In a healthy adult, the amount of cyanide produced at infusion rates up to about 2 µg/kg/min is typically manageable, but above this rate the detox system can be overwhelmed, allowing cyanide to accumulate and cause toxicity (myocardial and tissue hypoxia, lactic acidosis, altered mental status). That’s why 2 µg/kg/min is the threshold at which cyanide toxicity becomes a concern. If higher BP control is needed, clinicians usually use lower rates with careful monitoring, shorten duration, or switch to alternative agents to avoid toxicity.

Sodium nitroprusside releases cyanide as it dilates vessels, and the body can detoxify only a limited cyanide load at a time. In a healthy adult, the amount of cyanide produced at infusion rates up to about 2 µg/kg/min is typically manageable, but above this rate the detox system can be overwhelmed, allowing cyanide to accumulate and cause toxicity (myocardial and tissue hypoxia, lactic acidosis, altered mental status). That’s why 2 µg/kg/min is the threshold at which cyanide toxicity becomes a concern. If higher BP control is needed, clinicians usually use lower rates with careful monitoring, shorten duration, or switch to alternative agents to avoid toxicity.