Pharmacology of Ethanol Flashcards Preview

Nervous System: Unit IV > Pharmacology of Ethanol > Flashcards

Flashcards in Pharmacology of Ethanol Deck (17)
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1

Absorption of alcohol

  • Absorption: is rapid throughout entire GI tract; extremely rapid in small intestine.
  • The more rapid the ingestion, the more rapid the absorption (dependent on concentration gradient).
  • Presence of food slows absorption via delaying passage to small intestine, where extent and rate of absorption is greatest (a heavy meal can decrease peak concentration by 30%).

2

Characteristics of alcohol distribution

  • Distribution: Evenly distributed throughout all tissues and all fluids of the body.    
    • except: fat contains less water and less alcohol
  • Distribution / equilibration is most rapid in areas of high blood flow (brain, liver, kidney, lung).
  • Initial CNS effects within 5 min; peak effects within 15-60 min.

3

Characteristics of metabolism of ethanol

  • 98% liver - ADH and CYP2E1
  • Small amount expired, urinated unchanged
  • Zero order kinetics : 7-10 grams/hr

4

Characteristis of antabuse (disulfiram)

  • Antabuse is an aldehyde dehydrogenase inhibitor.
  • Disulfiram administration ==> 5-10 fold increase in acetaldehyde levels
  • ==> nausea/vomiting, respiratory and cardiovascular collapse, convulsions 

5

Role of NADH in alcohol metabolism

  • For the oxidative reactions to continue the NADH that is formed must be oxidized to NAD.
  • Mitochondrial oxidation of NADH to NAD is insufficient with the increased levels of NADH
  • ==> disruptions in hepatic metabolic pathways

6

Metabolic disruptions associated with alcohol abuse

  • ↑ Blood lactate → acidosis, behavioral disturbances
  • ↑ Mg2+ excretion →  can lead to convulsions
  • ↓ Uric acid excretion →  may precipitate gout attacks
  • ↑ Acetyl CoA →  ↑ fatty acid synthesis combine with ↓ fat breakdown →  fatty liver
  • ↑ NADH → ↓ Krebs cycle activity, ↓ gluconeogenesis →  hypoglycemia

7

Effects of ethanol @ CNS

  • depressant, sedative
  • loss of inhibitions
  • impaired reaction times, impaired judgement,
  • emesis
  • stupor
  • respiratory depression
  • analgesia
  • anticonvulsive
  • sleep effects

8

Effects of ethanol on liver

  • reversible damage → cirrhosis

  • ascites

  • varicosities

  • increased bleeding time

9

Effects of ethanol @ kidney

inhibits secretion of ADH → diuretic effect

10

Effects of ethanol @ GI

  • ulceration, bleeding
  • pancreatitis
  • decreased absorbtion of vitamins

11

Effects of ethanol on fetus

  • Prenatal or postnatal growth retardation
  • AND altered morphogenesis (especially facial dysmorphology)
  • AND CNS involvement (often mental retardation).
    • 1st trimester = altered morphology
    • 2nd = increased risk spontaneous miscarriage
    • 3rd = decreased growth

12

Tolerance development w/ethanol

  • Development of tolerance (limited compared to opioids) and physical dependence.                
  • Cross tolerance with other CNS depressants such as anesthetics and benzodiazepines.

13

Characteristics of early/minor w/drawal from ethanol

  • onset: 0-48 hrs
  • severity: mild - severe
  • sx:
    • mild agitation
    • anxiety
    • restlessness
    • tremor
    • anorexia
    • insomnia
  • seizures 6-48 hrs after onset of AWS

14

Characteristics of late/major/DT w/drawal from ethanol

  • onset: 24-150 hrs
  • severity: potentially life-threatening
  • sx:
    • extreme overactivity
    • disorientation
    • confusion
    • disordered sensory perception
    • NO seizures

15

Major drug interactions associate w/ethanol use

  • Additive effects with CNS depressants
  • Promotes GI bleeding if taken with aspirin
  • Can alter liver’s processing of other drugs
  • Disulfiram-like symptoms if taken with metronidazole or certain oral hypoglycemics.    

16

Management of acute alchohol intoxication

  • Support of respiration
  • administration of IV fluids; glucose, thiamine, and electrolytes (K+ and Mg++)
  • No specific antidote available

17

Management of acute alcohol w/drawal

  • Benzodiazepines
  • α2 agonists (clonidine) for signs of autonomic hyperactivity