Pharmacology

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Pharmacology

• Unit III

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Schizophrenia

• Positive symptoms hallucination, delusion,
  disordered thinking, agitation etc.
• Negative symptoms emotional withdrawl, lack of
  motivation, poor self-care etc.

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• Conventional antipsychotic agents relieve
  positive symptoms better
• Atypical antispychotic agents relieve both
  positive and negative

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• Potency
• Block dopamine 2 receptors for therapeutic
  effects probably
• Block dopamine, acetylcholine, histamine, and
  norepinephrine for adverse effects

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• Used for schizophrenia, bipolar disorder,
  Tourettes syndrome, prevention of emesis, other
  disorders including Huntingtons chorea

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Adverse Effects

• Extrapyramidal symptoms
• Movement disorders probably from Dopamine
  blockade

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Acute dystonia

• Early spasm of muscles of tongue, face, neck,
  or back. Laryngeal spasm dangerous
• Treatment with anticholinergic med, benztropine,
  diphenhydramine

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Parkinsonism

• Bradykinesia, mask-like facial feature, drooling,
  tremor, rigidity, shuffling gait, cogwheeling,
  stooped posture
• First month of therapy
• Benzotropine, diphenhydramine, amantadine
  (Symmetrel)
• May resolve spontaneously withdraw meds to see
  if needed

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Akathisia

• Need to be in motion very restless
• First few months of therapy
• Beta blockers, benzodiazepines, anticholinergic
  drugs decrease dosage or change to lower potency

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Tardive dyskinesia

• More with longer term therapy
• Worm-like movements of tongue and face,
  lip-smacking, fly-catching movements
• Interfere with eating
• May be irreversible may be due to
  supersensitive receptors to dopamine activation

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Neuroleptic Malignant syndrome

• Rigidity, high high high fever
• High blood pressure, extreme tachycardia
• Take off anti-psychotic, treat fever, blood
  pressure, rigidity, etc.

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Other adverse effects

• Anticholinergic effects
• Orthostatic hypotension
• Sedation
• Neuroendocrine
• Seizures
• Sexual dysfunction

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Low potency

• Chlorpromazine (thorazine)
• Thioridazine (mellaril)

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Medium potency

• Loxapine (Loxitane)

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High potency

• Haloperidol few side effects
• Fluphenazine prolixin
• Trifluoperazine stelazine

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Atypical antipsychotic agents

• Few EPS symptoms
• Relieve positive and negative symptoms

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• Clozapine (clozarpil) low affinity for Dopamine
  2 blockade, blocks serotonin receptors
• Causes agranulocytosis
• Monitor blood counts and early symptoms of
  infection

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• Risperidone lower incidence of side effects

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Antidepressants

• Depressed mood, loss of pleasure or interest in
  ones usual activities 5 symptoms present most
  of day every day for at least two weeks

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Tricyclic antidepressants

• Chemically nucleus has 3 rings
• Blocks reuptake of NE and serotonin hence
  monoamine theory of depression
• Takes at least two weeks for symptom relief
  take at least one month before evaluating med
  therapy

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Adverse effects

• Orthostatic hypotension, anticholinergic effects,
  sedation, cardiac toxicity, seizures, yawngasm

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Precautions

• Overdose! Life-threatening

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Selective Serotonin reuptake inhibitors

• Death by overdose rare, less undesirable side
  effects

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Fluoxetine - Prozac

• Inhibition of serotonin reuptake
• Uses depression, Obsessive-compulsive disorder,
  bulimia, panic disorders, PMS
• At least two weeks before symptoms start to abate

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Adverse effects

• Sexual dysfunction, nausea, headache,
  nervousness, anxiety, weight gain, serotonin
  syndrome
• Taper drug off

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Other SSRIs

• Zoloft, Paxil, Celexa, Luvox

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MAOIs

• Last choice for treatment except atypical
  depression
• Tyramine-containing foods can cause hypertensive
  crisis

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Adverse effects

• Excessive stimulation (CNS)
• Orthostatic hypotension
• Hypertensive crisis if patient eats foods with
  tyramine
• LOTS OF DRUG INTERACTIONS

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Atypical antidepressants

• Wellbutrin similar to amphetamine
• Trazodone (Desyrel)
• Nefazodone (Serzone)
• Venlafaxine (Effexor)
• Mirtazepine(Remeron)
• Amoxapine(Asendin)
• Reboxetin(Vestra)

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Drugs for bipolar disorder

• Alternating episodes of manic episodes and
  depression separated by periods of normal mood

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Lithium

• Short half-life, narrow therapeutic
  index!!!!!!!!!!!!!
• Lithium levels must be kept below 1.5 mEq
  toxicity can occur
• Maintenance levels should be 0.4-1.0mEq/L

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Toxic effects

• Toxicity can occur easily with patients who have
  sodium depletion
• Table 32-3 page 334
• Prevention monitor levels
• Overdose need hospitalization, dialysis may help

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Adverse effects

• GI, fatigue, muscle weakness, tremor, polyuria,
  birth defects first trimester

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Anticonvulsants

• Carbamazepine (Tegretol)
• Valproic Acid (Depakote)

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Benzodiazepines

• Anxiety and insomnia
• Antianxiety - hypnotics
• Work on limbic system
• Potentiate actions of gamma-aminobutyric acid
  (inhibitory transmitter of CNS)

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• Also used as for seizure treatment
• Lower incidence of side effects
• IV - respiratory depression
• Lower abuse potential manage toxicity

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