chapter 27 central nervous system sedatives and hypnotics
TRANSCRIPT
Chapter 27
Central Nervous System Sedatives and Hypnotics
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Sedatives and Hypnotics
Classifications Barbiturates Benzodiazepines Nonbarbiturates Miscellaneous
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Barbiturates
Act on the reticular formation area Reduce nerve impulses to the cerebral
cortex Inhibit nerve impulse transmission by
potentiating an inhibitory amino acid known as gamma-aminobutyric acid (GABA)
Effects are dose related
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Effect of Barbiturates
In low doses act as sedatives In higher doses act as hypnotics
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Barbiturates: Side Effects
Barbiturates raise the seizure threshold Reduce seizures
Used for treatment of status epilepticus, tetanus, and drug-induced convulsions
A select few are used as prophylaxis for epileptic seizures.
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Barbiturates: Side Effects
Main side effects Excessive central nervous system
depression Drowsiness, lethargy, dizziness, hangover
Hypersensitivity reactions Paradoxical restlessness or excitement Depression of the REM sleep cycle
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Barbiturates: Rebound Phenomenon
When barbiturates are discontinued, a rebound phenomenon can occur
Increase in REM sleep Dreams often become nightmares
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Benzodiazepines
Affect the hypothalamic, thalamic, and limbic systems of the brain and depress the CNS
Receptors resemble the GABA receptors
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Benzodiazepines
Useful hypnotic agents Have a calming effect on the CNS Control agitation and anxiety Relaxes skeletal muscle Does not affect the REM sleep cycle Used in the treatment of alcohol
withdrawal
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Benzodiazepines
An overdose results in somnolence, confusion, coma, and diminished reflexes
Treatment is syrup of Ipecac Activated charcoal with gastric lavage Treatment is flumazenil (Romazicon)
Reverses the sedative effects of benzodiazepines
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Alcohol
A potent CNS depressant Used to assist a person in relaxing and
becoming more social
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Other Sedatives
Zolpidem tartrate (Ambien) A nonbarbiturate, nonbenzodiazepine
hypnotic agent Produces an effect similar to the
benzodiazepines, but without producing muscle relaxation
Used frequently in the elderly