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Sedative hypnotics and anxiolytics
- Alcohol
- Barbiturates
- Non-barbiturate hypnotics
- Anxiolytics
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Alcohol that is NOT consumed
- Isopropyl alcohol (rubbing alcohol)
- Methyl alcohol (methanol)
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Alcohol that is consumed
- Ethyl alcohol
- Product of fermentation
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Absorption and distribution
- Oral administration
- Absorbed in small intestine
- Easily distributes throughout body
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Elimination and excretion
- Small amounts eliminated unchanged -> sweat, tears, urine, breath
- Most metabolized in liver by alcohol dehydrogenase
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Metabolism
- Alcohol dehydrogenase
- Ethanol -> acetaldehyde -> water and CO2
- Enzyme is rate-limiting (6-8 g/hr)
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Oxidation
- MIcrosomal ethanol oxidizing system
- Usually only 5-10% of metabolism
- Up to 50-60% with chronic consumption
- Role in cross-tolerance to barbiturates
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Effects on physiology and behavior
- No accepted medical use except aseptic
- Blood circulation
- Inhibition of ADH
- Sensory-motor function impaired
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Effects on cognition and affect
- 100-150 mg/100mL -> disinhibition
- 150-300 -> sedative effects
- 300 -> stupor
- 400 -> lethal, respiratory depression
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Mechanisms of action
- Membrane fluidity
- Membrane bound proteins
- GABAa receptor
- NMDA receptor
- CA neurotransmission
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Fetal alcohol syndrome
- Alcohol readily passes placenta
- Causes neurotoxic syndrome characterized by neurobehavioral problems
- Influences brain development during neurogenesis -> decreased brain weight
- Blockade of NMDA receptors during development triggers apoptosis
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