Lecture 8: Salicylate Poisoning Flashcards
What is the chemical name for aspirin
Acetylsalicylic acid
What is aspirin metabolised to and by what enzyme
hydrolysed to salicylic acid by esterases
How is the acetyl component of aspirin excreted
As CO2 after Kreb’s cycle
What are the 4 main metabolites of salicylic acid
- Salicyluric acid
- Gentisic acid
- Salicyl acyl glucuronide
- Salicyl phenolic glucuronide
How is elimination of salicylate affected as concentration increases
- Increase in elimination half-life as conc increases
- Increased Vd as conc increases
Common features in salicylate poisoning
- Vomiting
- Tinnitus/ deafness (characteristic as salicylate conc rises)
- Sweating
- Hyperventilation
- Fluid loss
Common features in very high salicylate poisoning
- Fever
- Confusion
- Tremor
- Blurring of vision
- Coma
Why do the features of very high salicylate poisoning occur
due to salicylate getting into the brain
Uncommon features of salicylate poisoning
- pulmonary edema
- cerebral edema
- Acute renal failure
- Epigastric discomfort
Metabolic features of Salicylate poisoning (5)
- Respiratory alkalosis
- Metabolic acidosis
- Mixed acid-base disturbances
- Hypokalaemia
- Hypo or Hyperglycemia
Definition of urine alkalinisation
- Treatment which increases poison elimination by administering IV sodium bicarbonate producing urine with pH >7.5
How does giving sodium bicarbonate increase urine pH
- lowers serum potassium concentration
Management of salicylate poisoning at plasma [salicylate] of <250 mg/L
- 50 - 100g AC if <1 hour after OD
- repeat concentration in 2 hours
Management of salicylate poisoning at plasma [salicylate] of 250-500 mg/L
- IV fluids
- correct metabolic acidosis
- repeat concentration in 2 hours
Management of salicylate poisoning at plasma [salicylate] of 500-700 mg/L
- IV fluids
- correct metabolic acidosis
- urine alkalinisation (pH >7.5)
- repeat concentration in 1 hour
