Psychiatric Agents

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Psychiatric Agents

• Andrew Healey, Instructor
• Matthew Miller, TAMDSC _at_ JHU-CTY BTH

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Classes of Drugs to cover briefly

• Sedative and hypnotic drugs
• Benzodiazepines know MOA (not explicitly
  taught)
• Antidepressants and antimanic drugs
• Antianxiety Drugs
• Antipsychotic drugs will not cover

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Sedatives

• reduce activity or excitement
• some degree of drowsiness common
• large does hypnotics
• state resembling natural sleep
• benzodiazepines, barbituates, others

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Benzodiazepines PT

• daytime sedation
• sedation before anethesia
• sleep inducement
• relief of anxiety and tension
• skeletal muscle relaxation
• anticonvulsant activity

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Benzodiazepines

• absorbed well from GI tract
• distributed widely
• some also given parenterally
• all metabolized in liver, excreted primarily in
  urine
• how do they work?
• YOU MUST KNOW THIS!!! (p. 262)

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Benzodiazepines

• help regulate emotional activity
• calm or sedate without causing drowsiness
• higher dosages, induce sleep
• increase time asleep
• sleep is deeper, more refreshing
• decrease time spent in REM sleep

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Barbituates

• sedatives and hypnotics
• barbital always in the name
• reduce overall CNS alertness
• standard pharmacokinetics
• appear to act through CNS

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Barbituates PT

• daytime sedation (short periods only)
• hypnotic effects (insomnia)
• preop sedation and anesthesia
• relief of anxiety
• anticonvulsant

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Barbituates PT

• Caution
• tolerance
• psychological / physical dependence
• benzodiazepines relatively effective and safe and
  effective gt almost replaced them as sedatives /
  hypnotics

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Antidepressants

• Affective disorders
• disurbances in mood, characterized by depression
  or elation
• MAO inhibitors
• tricyclic antidepressants (TCA)
• other antidepressants

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MAO inhibitors

• typical PK except excreted mainly in GI tract,
  and a bit by the kidnerys
• PD inhibit monoamine oxidase,
• enzyme that normally metabolizes the NTs
  norepinephrine and serotonin
• NE and serotonin stick around longer
• can interact with more receptors, longer

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MAO inhibitors

• also used to treat phobias and other psychiatric
  conditions
• lots of drug-drug and drug-food interactions
• lots of caution when using them!!

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Tricyclic Antidepressants

• amitriptyline
• imipramine hydrochloride
• can read about this large class of very common
  antidepressants

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Selective Serotonin Reuptake Inhibitors

• serotonin sticks around longer in synapse
• feel good molecule
• SSRIs have typically PK and are highly protein
  bound

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SSRIs

• used to treat major depressive episondes
• obsessive-compulsive disorder
• Zoloft gt post-traumatic stress distorder

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SSRIs

• Prozac (fluoxetine hydrochloride)
• Paxil (paroxetine hydrochloride)
• very effective, very interesting
• very important
• can take weeks before see therapeutic benefit!!

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Anxiolytics

• Some of the most commonly prescribed drugs
• Benzodiazepines
• Barbituates
• Buspirone

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Buspirone

• absorbed rapidly, extensive 1st pass
• metabolized to at least 1 active metabolite
• eliminated in urine and feces
• mechanism of action unclear
• does interact with GABA we think

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Lets review

• We only glazed the surface
• Wide variety of drugs in use a lot
• Sedative and hypnotic drugs
• Benzodiazepines know MOA
• Antidepressants and antimanic drugs
• Antianxiety drugs