Pharmacology: The Alcohols

The Alcohols

• Ethanol, Methanol, and Ethylene glycol are types of alcohols.

Ethanol

• Oldest recreational drug and most commonly abused drug in the world.
• Contributes to more morbidity, mortality, and public health costs than all illicit drugs combined.

Ethanol Consumption

• Has been documented as far back as 10,000 BC.
• Incorporated into religious festivals, used for pleasure, and in medicinal practice.
• Dangers of heavy consumption have long been recognized by almost all cultures.

Ethanol Consumption in the US

• Associated with other substance use and psychiatric disorders, often goes untreated.
• About 1/3 men and 1/4 women meet criteria for Alcohol Use Disorder (AUD).
• Excessive consumption causes 600,000 emergency department visits/year, 10% of deaths (≈85,000/year) in working adults, and 1/3 of fatal traffic accidents.

Physiological Effects

• Relatively large amounts are required for physiological effects.
• Consumed in gram quantities, unlike other drugs which are in milligram or microgram quantities.

Standard Drink

• Contains 14 g ethanol.
• Produces about 30 mg% blood ethanol concentration in a 70-kg person.

Blood Ethanol Concentration (BEC)

• Readily estimated by the measurement of ethanol levels in expired air.
• Determined by rate of drinking, sex, body weight, H2O percentage, rates of metabolism, and stomach emptying.

Absorption

• Rapid absorption via the stomach and small intestine, more in the latter.
• Tmax ≈ 30 mins without food.
• Cmax higher in women than in men.
• Delayed by food in the stomach due to slowing of gastric emptying.

Distribution

• Distributes to total body water.
• Tissue concentration approximates plasma concentration, especially in highly perfused tissues (e.g. the brain).
• Crosses the placenta.

Metabolism

• 90% metabolized in the liver.
• 2-step process:
  • Oxidation of ethanol to acetaldehyde via Alcohol Dehydrogenase (ADH) and Microsomal Ethanol-Oxidizing System (MEOS) pathways.
  • Oxidation of acetaldehyde to acetic acid.
• Kinetics:
  • Zero-order if BEC is >10 mg%.
  • First-order if BEC is <10 mg%.

The Alcohols

• Ethanol, Methanol, and Ethylene glycol are types of alcohols.

Ethanol

• Oldest recreational drug and most commonly abused drug in the world.
• Contributes to more morbidity, mortality, and public health costs than all illicit drugs combined.

Ethanol Consumption

• Has been documented as far back as 10,000 BC.
• Incorporated into religious festivals, used for pleasure, and in medicinal practice.
• Dangers of heavy consumption have long been recognized by almost all cultures.

Ethanol Consumption in the US

• Associated with other substance use and psychiatric disorders, often goes untreated.
• About 1/3 men and 1/4 women meet criteria for Alcohol Use Disorder (AUD).
• Excessive consumption causes 600,000 emergency department visits/year, 10% of deaths (≈85,000/year) in working adults, and 1/3 of fatal traffic accidents.

Physiological Effects

• Relatively large amounts are required for physiological effects.
• Consumed in gram quantities, unlike other drugs which are in milligram or microgram quantities.

Standard Drink

• Contains 14 g ethanol.
• Produces about 30 mg% blood ethanol concentration in a 70-kg person.

Blood Ethanol Concentration (BEC)

• Readily estimated by the measurement of ethanol levels in expired air.
• Determined by rate of drinking, sex, body weight, H2O percentage, rates of metabolism, and stomach emptying.

Absorption

• Rapid absorption via the stomach and small intestine, more in the latter.
• Tmax ≈ 30 mins without food.
• Cmax higher in women than in men.
• Delayed by food in the stomach due to slowing of gastric emptying.

Distribution

• Distributes to total body water.
• Tissue concentration approximates plasma concentration, especially in highly perfused tissues (e.g. the brain).
• Crosses the placenta.

Metabolism

• 90% metabolized in the liver.
• 2-step process:
  • Oxidation of ethanol to acetaldehyde via Alcohol Dehydrogenase (ADH) and Microsomal Ethanol-Oxidizing System (MEOS) pathways.
  • Oxidation of acetaldehyde to acetic acid.
• Kinetics:
  • Zero-order if BEC is >10 mg%.
  • First-order if BEC is <10 mg%.