Ethanol

Question 1

Where is alcohol most rapidly absorbed?

Answer 1

Small Intestine

Note that a heavy meal can decrease the peak concentration by 30%…though all of the alcohol still makes it to the blood, just more slowly.

Question 2

Where is alcohol distributed?

Answer 2

Water soluble = throughout all tissues and fluids of the body.

Crosses placenta.

More rapid in areas of high blood flow: brain, liver, kidney, lungs.

Initial CNS effects = 5 minutes.

Peak effects = 15 - 60 minutes.

More body fat = less alcohol absorbed = higher blood alcohol

Women have a lower blood alcohol level.

Question 3

How is alcohol eliminated?

Answer 3

Metabolism: 90 - 98% of removal.

Liver is primary organ, some is expired and peed out (2 - 10%)

Women have less gastric metabolism than men, so may account for a higher BAC than men.

Question 4

What is the rate of metabolism?

Answer 4

Zero order kinetics = constant rate.

Note, this means it always works at the same rate no matter the levels of blood alcohol.

Question 5

What are the 2 enzymes that convert ethanol to acetaldehyde?

Answer 5

1. alcohol dehydrogenase - in liver
2. CYP2E1 (mixed function oxidase)
   - works when BAC is high
   - can contribute 10 - 25% of ethanol metabolism

Question 6

What enzymes convert acetaldehyde to acetate?

Answer 6

Aldehyde dehydrongenase - in liver.

Anti-abuse drug disulfiram (Antabuse) inhibits aldehyde dehydrongenase.

Question 7

What if metabolism is insufficient and acetaldehyde builds up?

Answer 7

Acidosis,
Convulsions,
Gout attacks
Fatty liver
Hypoglycemia

Question 8

What affect does ethanol have on the CNS?

Answer 8

Acute:
Sedative-hypnotic effect.

Effects are proportional to the BAC (similar to barbiturates)

Note: NEVER a stimulant at any dose, but at low doses inhibits cortical neurons = a relative stimulatory phase.

Acts by altering neurotransmitter function.
Low doses = GABA interactions (enhancer) and glutamate NMDA (inhibits) interactions.

Is anticonvulsant, but withdrawal results in opposite.

Similar analgesia to morphine. Pain is perceived, but patient doesn’t care.

On sleep, similar to barbs, it suppresses REM.

Emetic.

Hangovers.

Question 9

What affect does ethanol have on the liver?

Answer 9

At first damage is reversible.

Cirrhosis can occur.
Can cause esophageal varicosities.
Can result in increased bleeding time (decrease in synthesis of clotting proteins).

Question 10

What affect does ethanol have on the kidney?

Answer 10

Diuretic effect by inhibiting antidiuretic hormone.

Question 11

What affect does ethanol have on the GI tract?

Answer 11

Irritant to the GI tract.
If taken with aspirin, can have ulcers.
Increases digestive secretions, can result in pancreatitis.
High doses can decrease absorption.

Question 12

What affect does ethanol have on the fetus?

Answer 12

Prenatal or postnatal growth retardation and altered morphogenesis and CNS involvement (retardation).

1st: morphologic abnormality
2nd: risk of spontaneous abortion
3rd: decreased growth

Question 13

What affect does ethanol have on the heart?

Answer 13

Vasodilator, increases hypothermia risk.

Can damage cardiac muscle increases blood pressure.

Question 14

When does withdrawal start?

When are peak symptoms of withdrawal?

When do seizures start?

Answer 14

When does withdrawal start: 0 - 48 hours post drink.

When are peak symptoms of withdrawal: within 24 - 36 hours.

When do seizures start: 6 - 48 hours after withdrawal starts

Question 15

How is alcohol withdrawal treated?

Answer 15

Benzos
Clonidine (alpha 2 adrenergic agonists)
More alcohol

Question 16

Alcoholics have poor oral health:

Answer 16

1. Poor oral hygiene in general, xerostomia
2. Increase periodontitis
3. increased bruxism
4. Poor nutrition = angular chelitis
5. Chronic inflamed tissues

Question 17

Alcoholics have unhealthy organ systems:

Answer 17

Liver:
Low protein levels = intra- or post-operative hemorrhage
Slow healing process.

Bone marrow:
Suppressed manufacture of platelets and leukocytes = prolonged bleeding, increased risk of infection.

Question 18

What are the alcohol-drug interactions specific to dentistry?

Answer 18

Tolerant to ethanol (but NOT acutely intoxicated) = cross-tolerance to benzos, barbs, N2O, and general anesthetic.

Acutely intoxicated = exaggerated response to opioids, benzos, barbs, N2O, general anesthetics

Question 19

What to use for pain in alcoholics?

Answer 19

Aspirin an dNSAIDs, but be careful of GI irritation and bleeding.

Acetaminophin: be careful of additive hepatotoxicity.
–> limit total dose to 2 grams/day (rather than 4g!)