Rubbing Alcohol (Isopropyl) Ingestion During Prohibition: Historical Context and Toxicity

During U.S. Prohibition (1920–1933), industrial alcohols (denatured ethanol, methanol, isopropanol) were diverted for consumption, causing mass poisonings.

Rubbing Alcohol Composition

• Typically 70% isopropyl alcohol (isopropanol) + 30% water + denaturants (bitterants, color).
• Some formulations: 91% or 99% isopropanol.

Toxicokinetics

• Rapid GI absorption → peak 30–60 min.
• Metabolized by ADH → acetone (ketone, CNS depressant) + CO₂.
• No metabolic acidosis (unlike methanol → formic acid, ethylene glycol → oxalic acid).
• Half-life: 2.5–4 hrs (prolonged in overdose).

Clinical Effects

Dose	Effects
Low (intoxication)	Euphoria, ataxia, slurred speech, sedation, gastritis, ketonemia, ketonuria (fruity breath)
Moderate-Severe	Coma, respiratory depression, hypotension, hemorrhagic gastritis, pancreatitis, rhabdomyolysis
Lethal	~250 mL (8 oz) of 70% in adult. Death from respiratory arrest, cardiovascular collapse.

Key Differences from Ethanol

• 2–3× more potent CNS depressant per mM.
• No anion gap metabolic acidosis (acetone is not acidic).
• OSMOLAL GAP ↑ (isopropanol + acetone); ANION GAP normal.
• Urine ketones positive (nitroprusside detects acetone).

Management

• Supportive: airway, ventilation, IV fluids, vasopressors.
• No fomepizole (does not inhibit isopropanol metabolism effectively; not indicated).
• No ethanol blockade (worsens CNS depression).
• Hemodialysis: clears isopropanol and acetone efficiently. Indicated: coma, hemodynamic instability, massive ingestion, prolonged half-life.
• Gastric lavage/activated charcoal: not effective (rapid absorption, low binding).

Prohibition Legacy

Government denaturing formulas (methanol, pyridine, benzene) caused blindness, neuropathy, death. The "Noble Experiment" highlighted dangers of unregulated substitutes. Modern denaturants (bitrex) deter ingestion but toxicity remains if consumed.