Cyanide

Question 1

Source of cyanide?

Answer 1

• Cyanide and cyanide-hydrogen (HCN) is used in:
  
  • Chemical synthesis
  • Rodenticides
• Cyanide is also released after ingestion of some seeds (apricot, almond)

Question 2

Mechanism of action?

Answer 2

It binds to trivalent irons of cytochrome oxidase ==> inhibition of cellular respiration ==> lactic acidosis and cytotoxic hypoxia

Question 3

Symptoms?

Answer 3

• Increased respiration (stimulation of chemoreceptive cells)
• Hyperpnoes
• Convulsion
• Coma
• Asphyxia

Question 4

Detoxification?

Answer 4

Formation of SCN^- (thiocyanate) by rodanase enzyme (quick)

Question 5

Therapy?

Answer 5

• Formation of methemoglobin (amyl-nitrite, Na-nitrite IV, 3x10ml)
• Thiosulfate IV 50ml 25% –> thiocyanate formation –> urine excretion
• Co-EDTA

(O₂ potentiates the effect of the a.m. compound????)