ALCOHOL

Introduction Primarily in the form of ethyl alcohol

(ethanol), has occupied an important place in the history of humankind for at least 8000 years.

They provided important calories and nutrients and served as a main source of daily liquid intake

Alcohol in low to moderate amounts relieves anxiety and fosters a feeling of well-being or even euphoria

Alcohol slows down the mind and body leaving the person unable to think or react, and make decisions he normally would.

Absorbed into the blood stream very quickly (within 5-10 minutes)

Passes from stomach directly into blood stream.

Affects every organ including the brain.

People who have develop dependence on alcohol are called alcoholics.

Alcoholism

Disease in which a person has physical or psychological dependence on drinks that contain alcohol.

Characterized as an impaired ability to study, work, or socialize normally.

Effects of alcohol Alcohol is a central nervous system

depressant. When ingested, alcohol passes from

the stomach into the small intestine, where it is rapidly absorbed into the blood and distributed throughout the body and it can affect the central nervous system even in small concentrations.

As blood alcohol concentration increases, a person's response to stimuli decreases markedly, speech becomes slurred, and he or she becomes unsteady and has trouble walking.

With very high concentrations - greater than 0.35 grams/100 milliliters of blood a person can become comatose and die.

Stages of alcohol intoxication

BAC (g/100 ml of blood)

Stage Clinical symptoms

0.01 - 0.05 Subclinical Behavior nearly normal by ordinary observation

0.03 - 0.12 EuphoriaMild euphoria, sociability, talkitivenessIncreased self-confidence; decreased inhibitions

0.09 - 0.25 Excitement

Emotional instability; loss of critical judgment impairment of perception, memory and comprehension

0.18 - 0.30 Confusion

Disorientation, mental confusion; dizzinessExaggerated emotional statesDisturbances of vision and of perception of color, form

0.25 - 0.40 Stupor

Markedly decreased response to stimuli; inability to stand or walk Vomiting; incontinence

0.35 - 0.50 Coma

Complete unconsciousnessDepressed or abolished reflexes Subnormal body temperatureIncontinenceImpairment of circulation and respirationPossible death

0.45 + DeathDeath from respiratory arrest

The primary pathway for alcohol metabolism involves alcohol dehydrogenase (ADH), a cytosolic enzyme that catalyzes the conversion of alcohol to acetaldehyde. It uses NADH as a cofactor in metabolism of ethanol.

Acetaldehyde, formed in the liver, is catalyzed by mitochondrial NAD-dependent aldehyde dehydrogenase. The product is acetate.

Disulfiram

Oxidation of acetaldehyde is inhibited by disulfiram, a drug that has been used to deter drinking by alcohol-dependent patients undergoing treatment

When ethanol is consumed in the presence of disulfiram, acetaldehyde accumulates and causes an unpleasant reaction of facial flushing, nausea, vomiting, dizziness, and headache.

Distribution Alcohol has a high affinity for water

and is therefore found in body tissues and fluids inasmuch as they contain water.

Absorbed alcohol is rapidly carried throughout the body in the blood and once absorption of alcohol is complete an equilibrium occurs such that blood at all points in the system contains approximately the same concentration of alcohol.

Elimination

The liver is responsible for the elimination - through metabolism - of 95% of ingested alcohol from the body. 

The remainder of the alcohol is eliminated through excretion of alcohol in breath, urine, sweat, feces, milk and saliva. 

End