nitroprusside
Table of Contents
sodium nitroprusside
see also:
introduction
- potent, rapid direct-acting that greatly reduces arterial blood pressure
- relaxes both venous and arterial circulation
- half-life of nitroprusside is 2 minutes (metabolised to cyanide by eryythrocytes then to thiocyanate in the liver)
- half-life of thiocyanate toxic metabolite is 3 days (excreted in kidneys)
administration
- must be given by iv infusion
- onset within minutes
- duration of action 1-10 minutes after cessation of infusion
- initial dose for hypertensive emergency is 0.3mcg/kg/min slowly titrated to max. 10mcg/kg/min if needed, although infusion rates > 2mcg/kg/min may risk accumulation of cyanide ions
- solution must be prepared fresh using 5% glucose, and protected from light, and discarded after 24hrs or if it turns blue, green or dark red (it should have a faint brown tinge)
contraindications
- hypotension
- hypersensitivity to nitroprusside
- cerebrovascular disease
- coronary artery disease
- liver disease
- renal impairment
- B12 deficiency
precautions
- hypothyroidism
- hypothermia
- lung disease
adverse effects
- hypotension
- tachycardia
- dizziness
- sweating
- headaches
- anxiety
- abdominal cramps
- hypothyroidism
- flushing
- rash
- muscle twitching
cyanide toxicity
- cyanide toxicity may cause:
- tachycardia, sweating, hyperventilation, metabolic acidosis, hypotension, arrythmias, death.
- Rx includes ceasing infusion, consider, iv sodium nitrite and sodium thiosulphate to increase metabolism to thiocyanate
thiocyanate toxicity
- thiocyanate toxicity is rarely a problem but may cause:
- nausea, SOB, blurred vision, confusion, psychosis and tinnitus
- Rx may be haemodialysis
nitroprusside.txt · Last modified: 2013/10/29 07:14 by 127.0.0.1