Pharmacology

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					    Pharmacology –
   Unit 2 – Spring 09
 Carla Hilton, MSN, RN, CNE
Lecture 2: Chapters 32, 34 & 37
        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.
 Classification:
Antidepressants
   Chapter 32
               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 one’s usual activities
• Under-treated
• More prevalent in women
• Suicidal thoughts may increase w Rx
  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 doesn’t get
    dissolved as quickly, keep producing it’s effect.)
  – Other uses: bipolar disorder, neuropathic pain, insomnia,
    fibromyalgia, OCD, bladder disorders
  – Just b/c they’re taking this, doesn’t mean they are depressed…
• Adverse effects
  – Orthostatic hypotension, sedation, anticholinergic effects
    (neurotransmitter effects), sedation, diaphoresis, cardiotoxicity,
    seizures, hypomania (they aren’t very interactive with you,
    “yawngasm”- orgasm that happens when you yawn
  – Because it effects neurotransmitters, it has an effect over the entire
    body
                    14-2
           Anticholinergic 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
                           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 – don’t give more than a week supply
     (so they won’t take them all…)
   – Dose at bedtime once levels achieved – EXCEPT in elderly
     (cardiac reasons) (when you’re vertical the fluids in your body
     they migrate down your body. When you’re laying down the
     fluids all go back into the system)
            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
            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 don’t 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
    wouldn’t really want to take this.
       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. John’s Wort Box 32-2
        Nursing Implications
ATI p. 203 (220)
  Classification:
Sedative-Hypnotics
     Chapter 34
                     Overview
• Venacular
  – Anti-anxiety, anti-anxiolytics, tranquilizers
  – Hypnotics
• Major Categories
  – Benzodiazepines, Barbiturates, Barbiturate–Like
  – 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
          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!
                  Benzos (cont’d)
• 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 don’t 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
        Nursing Implications
• ATI pp. 218
        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
             Melatonin Agonist
• Prototype: ramelteon [Rozerem]
• MOA / TE / Use
   – Activates melatonin receptors and rapidly induces
     sleep to treat insomnia (melatonin causes sleepiness)
• Adverse effects
   – Somnolence (you’re kind of apathetic), dizziness, and
     fatigue, reduced libido
• Precautions…
   – ETOH, liver impairment, dangerous activities
                          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
Drug Abuse

 Chapter 37
                            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 you’re 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
Table 37-1 DSM-IV-TR Diagnostic Criteria for
Substance Abuse and Substance Dependence

				
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