Psychopharmacology
BY
Pat Woodbery, MSN, ARNP-CS
Psychopharmacology
All psychopharmacological drugs produce their therapeutic effects by influencing synaptic transmission of neurotransmitters
GABA: mood
Serotonin: mood
Norepinephrine: alertness
Dopamine: thinking
Aceteylcholine: cognition
Synaptic Junction
Antianxiety Drugs
Alprazolam (Xanax) Short Acting
Diazepam (Valium) Long Acting
Benzodiazepines
Drugs of abuse
Cause physiologic dependence
Watch for withdrawal symptoms
Benzodiazepines
Mechanism of action
Enhances the effect of GABA
Causes muscle relaxation
Does not interfere with REM sleep
Safe, unless taken with CNS depressants like ETOH
Antianxiety Drug
Buspirone (BuSpar)
Not a benzodiazepine
Interacts with serotonin and dopamine
Does not cause muscle relaxation
Does not cause sedation
Does not cause dependance
Antianxiety Drugs
Indications for Use
Treat anxiety disorders
Phobias, panic, obsessive compulsive disorders (OCD), post-traumatic stress disorder (PTSD), atypical disorders and generalized anxiety disorder (GAD)
Preoperative sedation
Prevention of agitation
Treat withdrawal from ETOH
Contraindications
Antianxiety Drugs
Severe respiratory disorders
ETOH/drug abuse history
When CNS depressants are already in use
Client Teaching
Addicting
Control substance (theft)
Don’t discontinue suddenly, taper
Safety precautions: falls, machinery
Avoid ETOH and other CNS depressants
Early Withdrawal Manifestations
Anxiety
Insomnia
Irritability
Tremor
Palpitations
Headache
Later Withdrawal Manifestations
Confusion
Psychosis
Seizures
Benzodiazepine Toxicity
Flumazenil (Anexate) = Antidote
Reverses sedation, coma and respiratory depression caused by benzodiazepines. It has NO effect on opioids, ETOH, Barbiturates
Given IV
Slow administration with repeated dosing
Nursing Actions
Observe for therapeutic effects
Observe for excessive sedation
Observe for drug interactions
Antidepressants
Indications for Use
Depression
Panic disorders
Smoking cessation
Antidepressants
Mechanism of Action
Increase the availability of neurotransmitters by blocking their reuptake
Chemical Groups for Antidepressants
1.Tricyclic (TCA)
2.Selective Serotonin reuptake inhibitors (SSRI)
3.Monoamine Oxidase inhibitors (MAOI)
4.Miscellaneous
Tricyclic Antidepressant
Amitriptyline (Elavil)
First generation antidepressant
Increases norepinephrine and serotonin
Not used as the first line of treatment
Should NOT be used for elderly
High incidence of sedation
Hypotension
Arrhythmias
Selective Serotonin Reuptake
Inhibitors
Fluoxetine (Prozac)
Selects serotonin and inhibits it’s reuptake
First line treatment
Watch for anxiety, restlessness
Monoamine Oxidase Inhibitor
Tranylcypromine (Parnate)
Not used as first line treatment
Inhibits MAO which metabolizes norepinephrine and serotonin
MAO is also responsible for metabolism of tyramines. If tyramines are not metabolized then blood vessels constrict
Hypertension
Chest pain intracranial bleed
Tyramine Rich Food
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Red wine, beer, aged cheese, smoked meats, organ meats, yeast extracts
Client Teaching
Avoid tyramine rich foods because of chance of hypertensive crisis
Do not stop abruptly
Do not take with other antidepressant drugs
Miscellaneous
Bupropion (Wellbutrin)
Inhibits dopamine, norepinephrine, serotonin
Watch for anxiety
Client Teaching for Antidepressants
Monitor suicide
Orthostatic hypotension
Anticholenergic effects
Avoid ETOH and other CNS depressants
Evidence of successful treatment 2-4 weeks
Do not stop abruptly-taper
Dizziness, nausea, headache, mood disturbance, suicide
Mood Stabilizing Agent
Lithium Carbonate (Eskalith)
Mechanism of action: unknown
Indications for use: bipolar disorder
Contraindications: renal failure, thyroid malfunction, pregnancy
Side effects: memory loss, tremors, weight gain, thirst
Lithium Toxicity
Causes:
Water loss (vomiting,diarrhea, dehydration)
Overdose
Normal range 1.0 to 1.5 mEq/L
Manifestations
Lithium Toxicity
Mild Toxicity:
Lethargy, drowsiness, muscle weakness,
twitching, ataxia
Moderate Toxicity:
N/V, diarrhea, slurred speech, blurred vision
Severe Toxicity: (2.5 mEq/L)
Hallucinations, oliguria, seizures, coma,
death
Nursing Actions
Lithium Toxicity
Stop Drug
Hydrate
Stabilize Vascular System
Severe=Dialysis
Antipsychotic Drugs
Used mainly to treat psychosis
Psychosis is seen as altered thinking
Hallucinations, delusions, bizarre behaviors
Psychosis = elevated dopamine at synaptic junction
Synaptic Junction
Antipsychotic Drugs
Haloperidol (Haldol)
Typical
Risperidone (Risperdal)
Atypical
Occupy or block dopamine receptors
Decrease dopamine at the receptor site
Indications for Use of Antipsychotic Drugs
Schizophrenia
Psychotic symptoms caused by:
Head injury
Stroke
ETOH withdrawal
Medications
Client Teaching
Look for therapeutic effects
Look for side effects:
Dry mouth
Sun sensitive
Extrapyramidal symptoms (EPS)
Anticholinergic effects
Do not discontinue
Extrapyramidal Effects
Akathisia
Parkinsonism
Dyskinesias
Tardive Dyskinesia
Anticholinergic Effects
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Hypotension, tachycardia, dizziness, dry mouth, blurred vision, constipation, urinary retention
Nursing Actions
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Observe for therapeutic effects
Observe for toxic effects
Identify Neuroleptic malignant syndrome (NMS)
Antiparkinson Drugs
Antipsychotic medications can create Parkinson’s like symptoms due to blockade of DOPAMINE at synapse
Antiparkinson Drugs
Parkinson’s disease is characterized by:
1. Abnormalities in movement
2. Accelerated gait
3. Salivation, drooling
4. Pill rolling motions of hands
Prototype: Benztropine (Cogentin)
Treats Parkinson’s like symptoms by increasing the amount of Dopamine
Nursing Actions
Observe for therapeutic effects
Observe for anticholinergic effects
Tachycardia, palpitations, sedation, constipation, urinary retention