Pharmacology

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Pharmacology Unit 2 Spring 09

• Carla Hilton, MSN, RN, CNE
• Lecture 2 Chapters 32, 34 37

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Learning Outcomes

• Compare and contrast fundamental concepts related
  to the use of specific central nervous system
  drugs for sedation and depression with a look at
  major concepts related to abuse.
• Acquire a working framework for studying drug
  classifications and nursing implications.

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Classification Antidepressants

• Chapter 32

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General Points

• Most common psychiatric disorder
• Major treatment method - medications
• Five major groups
• Goal? (to make people feel better/functional)
• Sxms
• Depressed mood, loss of pleasure / interest in
  all or nearly all of ones usual activities
• Under-treated
• More prevalent in women
• Suicidal thoughts may increase w Rx

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Tricyclic Antidepressants (TCAs)

• Prototype imipramine Tofranil
• MOA TE / Use
• Blocks reuptake of the MAO transmitters NE
  (norepinephrine) and serotonin. Elevates mood,
  thereby treating depression. (it doesnt get
  dissolved as quickly, keep producing its
  effect.)
• Other uses bipolar disorder, neuropathic pain,
  insomnia, fibromyalgia, OCD, bladder disorders
• Just b/c theyre taking this, doesnt mean they
  are depressed
• Adverse effects
• Orthostatic hypotension, sedation,
  anticholinergic effects (neurotransmitter
  effects), sedation, diaphoresis, cardiotoxicity,
  seizures, hypomania (they arent very interactive
  with you, yawngasm- orgasm that happens when
  you yawn
• Because it effects neurotransmitters, it has an
  effect over the entire body

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14-2Anticholinergic Effects

• Salivary glands- decreased secretion
• Sweat glands- decreased secretion
• Bronchial glands- decreased secretion
• Heart- Increased rate
• Eye- mydriasis, blurred vision
• Urinary tract- interference with voiding
• Intestine- decreased tone and motility
• Lung- dilation of bronchi
• High Doses
• Stomach- decreased acid secretion

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TCAs

• Precautions / Interactions
• TCAs w MAOI can lead to severe HTN
• Potentiates drugs like NE (norepinephrine)
• Potentiate CNS depressants
• Antidote activated charcoal after gavage (go in
  and wash out the stomach and wash all the pills
  out)
• Dosing
• Based on clinical response dont give more than
  a week supply (so they wont take them all)
• Dose at bedtime once levels achieved EXCEPT in
  elderly (cardiac reasons) (when youre vertical
  the fluids in your body they migrate down your
  body. When youre laying down the fluids all go
  back into the system)

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SSRI Antidepressants

• Prototype fluoxetine Prozac
• MOA / TE / Use
• Selective serotonin re-uptake inhibitor resulting
  in elevated serotonin levels elevating mood and
  relieving depression.
• Helps in bulimia nervosa
• Adverse effects
• Impotence, weight gain, Serotonin syndrome (can
  make you agitated and angry), withdrawal
  syndrome, EPS (extraperamital side effects),
  bruxism (grinding your teeth), bleeding,
  hyponatremia.
• Interactions MAOIs, Warfarin (adverse effect of
  bleeding in SSRI, warfarin thins blood, they
  bleed lots), TCAs

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MAOI Antidepressants

• Prototype phenelzine Nardil
• MAO / TE / Use
• Enzyme deactivates NE, serotonin, dopamine,
  and tyramine (NE stimulator) from foods
• NOT 1st CHOICE b/c it causes lots of stimulation
• Use when all other anti-depression meds dont
  work
• Relevant P-kinetics
• Tyramine
• Adverse effects
• CNS stimulation agitation hypomania mania
  hypotension HTN crisis meperidine (demerol)
  (hyperpyrexia)
• You have to cut lots of good foods out of your
  diet, so the pt wouldnt really want to take
  this.

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Atypical Antidepressants

• Bupropion Wellbutrin
• Action unclear- often used in smoking cessation
• Effect
• Stimulant ergo no wt gain
• No sexual dysfunction may augment
• Adverse effects
• agitation, HA, dry mouth, constipation, wt loss,
  insomnia, tachycardia, seizure
• Note St. Johns Wort Box 32-2

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Nursing Implications

• ATI p. 203 (220)

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ClassificationSedative-Hypnotics

• Chapter 34

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Overview

• Venacular
• Anti-anxiety, anti-anxiolytics, tranquilizers
• Hypnotics
• Major Categories
• Benzodiazepines, Barbiturates, BarbiturateLike
• Miscellaneous
• Major Effects
• CNS depression (the whole head translates down to
  the whole body)
• Therapeutic Uses
• Relieve anxiety, facilitate sleep, manage muscle
  spasms, seizure and panic disorders, augment
  anesthesia, and manage ETOH withdrawal

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Benzodiazepines (CIV)Category D

• Prototype diazepam Valium
• Others clonazepam, lorazepam, clorazepate
• MOA
• Depress neuronal function at multiple CNS sites
  by potentiating endogenous GABA
  (gamma-aminobutyric acid) and is limited because
  GABA is finite?safer
• Cardiac
• Very safe PO, effect - heart blood vessels
• IV effect if given rapidly can cause super BP
  lowering
• Respiratory
• Minimal alone, serious if combo or IV
• Incompatible with everything in some forms!

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Benzos (contd)

• Pharmacokinetics
• Readily absorbed
• Differ in respect to time - course of action
• (main indicator for which one chosen for which
  job)
• Adverse effects
• CNS daytime vs nighttime impacts
• Amnesia (usually good b/c they dont remember the
  traumatic procedure)
• Paradoxical (it gets the opposite effect you were
  expecting)
• Abuse
• Malnutrition (low albumin means higher level of
  circulating drug), liver disease and blood levels
• D?D w other CNS depressants
• Dosage varies by agent

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Nursing Implications

• ATI pp. 218

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Benzodiazapine-likes

• Prototype Zolpidem Ambien CIV (class 4)
• MOA TE / Use
• Agonists at benzodiazepine receptor site on GABA
  channel prolonging sleep duration and helps
  relieve insomnia
• Low potential for tolerance or abuse
• Adverse effects
• Similar to benzodiazepines (daytime drowsiness /
  dizziness)
• Can intensify CNS depressants
• Dosage / Administration
• Before bedtime, you want it to kick in by the
  time you get into bed
• Sleepwalking problems and such

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Melatonin Agonist

• Prototype ramelteon Rozerem
• MOA / TE / Use
• Activates melatonin receptors and rapidly induces
  sleep to treat insomnia (melatonin causes
  sleepiness)
• Adverse effects
• Somnolence (youre kind of apathetic), dizziness,
  and fatigue, reduced libido
• Precautions
• ETOH, liver impairment, dangerous activities

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Barbiturates

• Prototype secobarbital Seconal
• MAO / TE / Use
• Mimics GABA and depresses CNS directly causing
  relaxation and anxiety reduction. Other uses
  seizure management, anesthesia, sleep disorders,
  mania
• ADME
• NO CEILING TO LIMITS OF CNS depression
• Adverse effects
• Resp. depression, hypotension in toxic doses, can
  readily cause death
• Precautions
• Highly addictive - physical dependence
  withdrawal can be severe
• Caution in elderly
• Caution with other CNS agents
• Caution with IM injection

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Drug Abuse

• Chapter 37

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Terms

• Drug abuse
• using a drug in a fashion inconsistent with
  medical or social norms
• Addiction- you have to have it! You will not eat
  and steal from your baby daddy to get your shiz
• Cross-tolerance- if you take a lot of hydrocodone
  the morphine might not do you much good. If
  youre used to a drug, you might be used to its
  drug cousin
• Psychological dependence- mentally addicted to
  chocolate/marijunana
• Physical dependence- your body freakin needs it!
• Cross-dependence- if you are dependent on a drug,
  you are very likely to become addicted to its
  drug cousin
• Withdrawal syndrome

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Table 37-1 DSM-IV-TR Diagnostic Criteria for
Substance Abuse and Substance Dependence