EM Toxicology 17: Isopropanol

Question 1

Remarks on Isopropanol

Answer 1

Isopropranol is twice as potent as ethanol in causing CNS depression

and its duration of action is 2-4x that of ethanol

As a result, it is often used as a substitute intoxicant by alcoholics as well as in suicide attempts

Question 2

Hallmarks of isopropanol toxicity

Answer 2

Ketosis and an osmolar gap without acidosis

Question 3

Principal metabolite of isopropanol

Answer 3

Acetone
- does not cause eye, kidney, cardiac, or metabolic toxicity
- although high levels of acetone may contribute to CNS depression

The long half-life (17-27 hours) of acetone may contribute to the prolonged mental status depression often associated with isopropanol

Question 4

toxic dose of 70% isopropanol

Answer 4

approx 1 mL/kg
although as little as 0.5 mL/kg may cause symptoms

Children are especially susceptible to toxic effects and may develop symptoms after as little as three swallows of 70% isopropanol

Question 5

minimum lethal dose for an adult has been reported as

Answer 5

approx 2 to 4 mL/kg
but survival has been reported following ingestions of up to 1L

Question 6

primary clinical toxicities of isopropanol

Answer 6

CNS depression caused by both parent compound and acetone
- if severe: coma, respiratory depression, hypotension

and gastric irritation from isopropanol itself
- n/v, pancreatitis, hemorrhagic gastritis

Question 7

other clinical features of isopropanol toxicity

Answer 7

Hypoglycemia (from increased NADH/NAD+)

Hypotension (from massive ingestion causing peripheral vasodilation)

rhabdomylosis and renal faiulre [have also been reported]

Question 8

treatment of isopropanol toxicity

Answer 8

Supportive

Do not give fomepizole or ethanol, because the acetone is no more toxic than isopropanol itself, and preventing isopranol metabolism may prolong CNS toxicity.

Monitor for respiratory/CNS depression, hypotension, GI bleed

Question 9

In isopropanol toxicity, consider hemodialysis if

Answer 9

hypotension is refractory to conventional therapy

or when isopropanol level is >400 mg/dL

Question 10

Disposition in isopropanol toxicity

Answer 10

discharge:
asymptomatic for 4-6 hours

admit:
lethargy or prolonged CNS depression
with high risk for self-harm