Alcohol: Toxic Levels & Intake History | Smoking Addiction History

1. Ethanol (Drinking Alcohol) — Toxic Levels

2. Methanol & Ethylene Glycol — Toxic Alcohol Levels

Methanol (CH₃OH)

• Minimum lethal dose (untreated): ~1 g/kg or ~100 mL in an adult
• The toxic range of methanol itself is thought to be 60–250 mL, though as little as 15 mL has caused death
• Asymptomatic: levels <20 mg/dL (<6 mmol/L)
• CNS symptoms: levels rising above 20 mg/dL
• Ocular toxicity (vision loss): levels >50 mg/dL (>16 mmol/L)
• Risk of fatality: levels >150–200 mg/dL (>47–62 mmol/L)
• Metabolized to formaldehyde → formic acid → blocks oxidative phosphorylation → anion gap metabolic acidosis
• Diagnosis: Methanol level >20 mg/dL + unexplained osmolar gap >10 mOsm/kg H₂O early; elevated anion gap metabolic acidosis later

Ethylene Glycol (antifreeze)

• Minimum lethal dose: 1.1–1.7 g/kg or ~100 mL in an adult
• Diagnosis threshold: level >20 mg/dL (>3.2 mmol/L)
• Metabolized to glycolic acid and calcium oxalate crystals → metabolic acidosis + renal failure
• Three clinical stages:
  1. CNS stage (0–12 h): Inebriation, hypocalcemia, seizures
  2. Cardiopulmonary stage (12–24 h): Tachycardia, multiorgan failure (most deaths here)
  3. Renal stage (24–72 h): Renal failure from oxalate crystal deposition in proximal tubules

Treatment for both: inhibit alcohol dehydrogenase with fomepizole (preferred) or ethanol infusion targeting ethanol level of 100–150 mg/dL. Continue until toxic alcohol level <20 mg/dL (methanol <6 mmol/L; ethylene glycol <3 mmol/L) and metabolic acidosis resolves.

3. Alcohol Intake History — Key Questions

• Which substances have been used, ever?
• Age of first use; length and pattern of use; date of most recent use

• What substances are currently used? How much and how frequently?
• Mode of ingestion; triggers for use

• History of withdrawal symptoms?
• Requiring more substance to achieve same effect (tolerance)?
• Cravings to use?

• Impact on physical/emotional health
• Social impact: employment, school, hobbies
• Risky or illegal behaviors

• Ever injected drugs? Shared equipment?
• History of overdose?

• Attempts to cut down or quit? Longest period of abstinence?
• Prior treatment or medications (e.g., naltrexone, acamprosate, disulfiram)?
• Current goals: abstinence, reduction, or harm reduction?

4. Smoking Addiction — History & Key Concepts

Clinical Importance of Smoking History

• Nicotine withdrawal: agitation, irritability, craving
• Clinically important drug interaction: Smoking induces CYP1A2 — abrupt cessation increases bioavailability of clozapine and olanzapine, risking over-sedation — Goldman-Cecil Medicine

Nicotine Dependence (DSM-5: Tobacco Use Disorder — TUD)

1. Using more tobacco than intended, over longer duration
2. Repeated failed attempts to quit
3. Significant time spent obtaining/using tobacco
4. Cravings/intense urge to use
5. Failure to fulfill major obligations at work/school/home
6. Continued use despite social/interpersonal problems
7. Withdrawal from activities due to tobacco use
8. Use in hazardous situations
9. Continued use despite physical/psychological harm
10. Tolerance (needing more for same effect)
11. Withdrawal on cessation

Why Nicotine Is Highly Addictive

• Rapid delivery to the brain via inhalation (faster than IV injection)
• Frequent reinforcement: ~10 puffs × 20 cigarettes/day × years = millions of drug self-administrations
• Precise dosing via manufactured cigarettes
• Industry additives (ammonia, menthol, sugars) deliberately boost addictive properties
• Classical conditioning: Conditioned cues (smell, sight, situations) trigger strong urges
• Genetic factors: CYP2A6 variants affect nicotine clearance rate; heritability comparable to alcohol dependence

• 90% of smokers begin as teenagers — adolescent initiation strongly predicts dependence

Obtaining the Smoking History

• Do you currently smoke, or have you ever smoked?
• How many cigarettes/day (pack-years)?
• Age started; how long smoking
• Prior quit attempts — methods used, duration of success, triggers for relapse
• Current motivation and readiness to quit
• Use of other nicotine products (e-cigarettes, chewing tobacco, patches)?
• Withdrawal symptoms when trying to stop?