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Flashcards in Drugs Used in CNS Deck (21):
1

Common psychiatric conditions

1. Anxiety disorder
2. Insomnia
3. Depressive disorder
4. Psychosis

2

Symptoms of anxiety disorders

1. Psychological symptoms
- apprehension, fear
2. Somatic symptoms
- CVS - palpitations, tremors
- Resp - chest pain, SOB
- GIT disturbances, hyperactivity
- Headaches, dizziness
- Loss of libido
- Muscle spasms
- Insomnia

3

Definition of insomnia

inability to fall asleep, maintain sleep or early morning wakening, affecting the function of the next day

4

Causes of insomnia (3)

1. Anxiety - increased emotional arousal
2. Drug induced, caffeine
3. Drug withdrawal - after chronic use of alcohol, sleeping pills

5

Drugs used for anxiety disorders & insomnia

1. Benzodiazepines
- Short Acting: Midazolam
- Intermediate Acting: Lorazepam, Alprazolam
- Longer Acting: Diazepam

2. Non-benzodiazepine hypnotics
- Zolpidem, Zopiclone

6

Mechanism of action of benzodiazepines

- BZD binds to specific BZD sites in the CNS
- increased freq of Cl channel opening - potentiates GABA actions
- GABA dependent, overdose is safe
- GABA is also an inhibitory neurotransmitter - helps sleep - faster onset but reduced REM & deep (stage 4) sleep compared to natural sleep (poorer quality)

7

Toxicity of benzodiazepines (6)

1. CNS - increased drowsiness, decreasd motor skills, prolonged reaction time
2. CNS - anterograde amnesia esp after IV sedation
3. CVS - decreased BP & resp rate
4. Paradoxical effects - excitement, garrulousness, irritability, hallucinations, outburst of rage (attributed to disinhibition by BZD)
5. Neonatal toxicity - floppy child syndrome
6. Tolerance, dependance, withdrawal

8

Toxicity of non-benzodiazepine hypnotics (2)

1. Withdrawal anxiety
2. Abuse potential

9

Symptoms of depression (6)

1. Decreased mood, interest
2. Feeling of shame, guilt
3. Suicidal ideation
4. Less sleep/appetite (or more - atypical depression)
5. Psychomotor retardation
6. Decreased concentration, energy

- symptoms persist for at least 2 weeks
- severity of symptoms interfere with normal functioning

10

Non pharmacological treatment of depression

- Psychological - cognitive behavioural therapy, interpersonal
- Social, behavioural, relaxation, counselling

11

Pharmacological treatment of depression (4)

1. Selective serotonin re-uptake inhibitors (SSRIs)
- Fluoxetine, Escitalopram, Sertraline, Paroxetine
2. Tricyclics (TCAs)
- Amitriptyline, Imipramine
3. Serotonin norepinephrine re-uptake inhibitors (SNRIs)
4. NaSSa - noradrenergic & specific serotonergic antidepressants

12

Mechanism of action of antidepressants

- block re-uptake transporters
- enables neurotransmitters present in synapse to continue acting on post synaptic neurons

13

Toxicity of SSRIs (4)

1. Anxiety
2. Weight loss/gain
3. Headache, nausea
4. Sexual dysfunction

- no fatality in overdose

14

Toxicity of TCAs (4)

1. Tachycardia, arryhthmias
2. Postural hypotension
3. Anti cholinergic effects - constipation, dry mouth, dry eyes, glaucoma, blurred vision
4. CNS effects - sedation, fatigue

15

Hypotheses of psychosis (2)

1. Excessive dopamine in mesocortico-limbic system
2. Abnormality in 5-HT, glutamate & other systems

16

Symptoms of schizophrenia

- type of psychosis

1. Positive symptoms
- delusion (abnormal belief), hallucination, disorganised thinking, speech, behaviour
2. Negative symptoms
- avolition, affect flattening, inability to plan, poor concentration

- duration of disturbances - 6m
- deterioration in social/occupational function
- anti psychotics work better on positive symptoms

17

Drugs used in psychoses

1. Typical (first gen)
- Trifluoperazine
- Haloperidol
- Depot flupentixol
2. Atypical (second gen)
- Risperidone
- Olarizapine
- Quetiapine
- Clozapine

18

Mechanism of action of antipsychotics

- blocks dopamine receptors in extrapyrimidal system, limbic midbrain, frontal cortex
- typical blocks D2 > 5HT2 receptors, atypical blocks 5HT2 > D2
- blocks D1, cholinergic, histaminic & alpha adrenergic

19

Toxicity of typical antipsychotics (6)

1. Extrapyrimidal effects
2. Anti-adrenergic effects
3. Anti-cholinergic effects
4. Metabolic & endocrine effects
5. Allergic effects
6. others

20

Toxicity of atypical antipsychotics (5)

1. Agranulocytosis (2%) - clozapine
2. Weight Gain - esp in clozapine, olanzapine
3. Sedation - clozapine, olanzapine
4. Extrapyrimidal (dose dep) - risperidone
5. Metabolic syndrome - quetiapine

21

Extrapyrimidal side effects (5)

1. Acute Dystonia
- spasm of muscles of tongue, face, neck, back, extraocular
2. Parkinsonism
- bradykinesia, rigidity, tremor, mask facies
3. Akathisia
- irresistable urge to move about, physical restlessness
4. Malignant syndrome
- catatonia, stupor, fever, unstable blood pressure, myoglobinemia, can be fatal
5. Tardive dyskinesia
- oral-facial dyskinesia
- widespread chloreoathetosis
- abnormal movement of trunk, pelvis