Drugs Used in Psychiatric Disorders Flashcards
What is the class of drugs commonly used as anxiolytics and as sleeping pills to treat the symptoms and behaviors caused by anxiety disorders?
Benzodiazepines
Name 5 examples of Benzodiazepines
Short acting: Midazolam
Intermediate acting: Lorazepam, Alprazolam
Long acting: Diazepam, Clonazepam
think lam and pam
What is the Mechanism of Action of Benzodiazepines?
BZD binds to specific BZD sites in the CNS and potentiates GABA actions by increasing the frequency of chloride channel opening induced by GABA.
It is GABA dependent. It does not open the channels in the absence of GABA so Cl- doesn’t enter the cells in the overdose of Benzodiazepines.
∴ Benzodiazepine is a safe drug in overdose
What is the route of administration for benzodiazepines?
Oral - fast onset 0.5 - 1 h
IV - immediate onset
Parenteral IV: Midazolam, Lorazepam, Diazepam
What are the active compounds of Diazepam, Lorazepam, Alprazolam and Midazolam?
Diazepam -> Nordazepam (L) -> Oxazepam (I)
Lorazepam (I) - active compound, trick question
Alprazolam (S) -> alpha-Hydroxyalprazolam (S)
Midazolam (S) -> alpha-Hydroxymidazolam (S)
NOTE: all active compounds then undergo glucuronidation
List 6 adverse effects of Benzodiazepines
- CNS: ↑ drowsiness, ↓ motor skills, ↑ reaction time
- CNS: Anterograde amnesia. Memory disturbances are particularly profound after IV sedation
- CVS: ↓ BP, ↓ respiration in predisposed patients
- Paradoxical effects: excitement, garrulousness (talkative), irritability, hallucination, outburst of rage.
Violent behaviour has been attributed to disinhibition by BZD (behaviour normally suppressed) - Neonatal toxicity: Floppy child syndrome
- Tolerance, dependence and withdrawal
What is the elimination half-lives of Benzodiazepine hypnotics?
2 - 24 h
What is insomnia?
Not able to fall asleep, maintain sleep or early morning wakening, affecting the function of next day
What causes insomnia?
A + 3Ds
Anxiety - increased emotional arousal
Depression
Drugs-induced (caffeine)
Drug withdrawal - after chronic use of alcohol or sleeping pills
What are the characteristics of Benzodiazepine - induced sleep?
Reduced REM and deep (stage 4) sleep when compared to natural sleep
Name 2 non-benzodiazepine hypnotics, their MoA and hypnotic effect
Zolpidem, Zopiclone
MoA & hypnotic effect similar to BZ
binds to specific BZD sites in the CNS and potentiates GABA actions by increasing the frequency of chloride channel opening induced by GABA
Name 2 adverse effects of non-benzodiazepine hypnotics
Withdrawal anxiety
Abuse potential
What is the elimination half-life of non-benzodiazepine hypnotics?
2 - 4 h
What are the symptoms of depression?
Mood down
Interest down
Feeling of shame / guilt
Suicidal ideation
Sleep less (or more)
Psychomotor retardation
Appetite down (or up)
Concentration down
Energy down
Symptoms persist for at least 2 weeks, and severity of symptoms interfere with normal functioning
What are non-pharmacological treatment for depression?
Psychological: Cognitive Behavioural Therapy, Interpersonal
Social
Behavioural
Relaxation
Counselling
Name 4 classes of antidepressants
- Selective Serotonin Re-uptake Inhibitors (SSRIs)
- TriCyclics Antidepressants (TCAs)
- Serotonin Norepinephrine Re-uptake Inhibitors (SNRIs)
- NorAdrenergic & Specific Serotonergic Antidepressants (NaSSAs)
Name 4 examples of SSRIs
Fluoxetine, escitalopram, sertraline, paroxetine
Name 2 examples of TCAs
Amitriptyline, imipramine
Name 1 example of SNRIs
Venlafaxine
Act like TCAs
Name 1 example of NaSSAs
Mirtazapine
Antagonist of alpha2-adrenergic receptor and certain serotonin receptors
MoA of SSRIs / SNRIs / TCAs
SSRI blocks serotonin transporter → ↑ serotonin in the brain
SNRI and TCA block serotonin transporter and norepinephrine transporter
→ ↑ serotonin and norepinephrine in the brain
List 5 adverse effects of SSRIs
- Anxiety
- Weight loss / gain
- Headache, nausea
- Sexual dysfunction
- Hyponatremia
No fatality in overdose (unlike TCAs)
What is the blood test that you need to do when a patient is treated with SSRI?
Blood Na+ levels
SSRIs - DDIs
- SSRIs inhibit various P450 enzymes
Fluoxetine > paroxetine > sertraline > escitalopram
ask for medication history when prescribing - Don’t take SSRIs with MAOI or St John’s wort
Risk of Serotonin syndrome: confusion, agitation, restlessness, stomach or intestinal symptoms, a sudden high body temperature, an extremely high BP or severe seizures
List 5 adverse effects of TCA
- CNS effects: sedation, fatigue
- Cardiac rhythm: tachycardia, arrhythmias
- Postural hypotension
- Anticholinergic effects: glaucoma, blurred vision, urinary retention, constipation
- FATALITY IN OVERDOSE
don’t give TCA to old man bc of anticholinergic effects
List 3 adverse effects of SNRIs
- CNS effects: agitation, irritable or drowsy
- CVS effects: BP may be raised at higher dose
- Hyponatremia
Unlike TCA, SNRI doesn’t have anticholinergic effects, postural hypotension and cardiac rhythm abnormalities
What are the symptoms of anxiety disorders?
Psychological symptoms:
- Apprehension and fear
Somatic symptoms:
- CVS: Palpitations
- Resp: Chest pain and shortness of breath
- GIT disturbance
- Headaches and dizziness
- Tense muscle
- Insomnia
What are the symptoms of schizophrenia?
Positive symptoms:
- delusion (abnormal belief), hallucination
- disorganized thinking, speech and behavior
Negative symptoms:
- no volition, no emotion, no expression
- no ability to plan, poor concentration
duration of disturbances: 6 months
deterioration in social / occupational function
List 2 classes of antipsychotic drugs to treat symptoms of psychoses and examples
- Typical (first generation):
high potency
Haloperidol - Atypical (second generation):
Risperidone
Olanzapine
Quetiapine
Clozapine
Aripiprazole
What is the MoA for typical (first generation) antipsychotics?
block D2 > serotonin (5-HT2) receptors
block D1, cholinergic, histaminic and alpha adrenergic
What is the MoA for atypical (second generation) antipsychotics?
block serotonin (5-HT2) > D2 receptors
block D1, cholinergic, histaminic and alpha adrenergic
List 4 adverse effects of typical (first gen) antipsychotic drugs / Haloperidol
- Extrapyramidal side effects (blocks dopamine) - characteristic of haloperidol
- Sedation
- Anticholinergic (blocks acetylcholine)
- Rare cases of neuroleptic malignant syndrome
List ADRs of atypical (2nd gen) antipsychotics
Less extrapyramidal side effects than typical (1st gen) antipsychotics
Clozapine: agranulocytosis in 2% of patients, weight gain, sedation
Olanzapine: severe WEIGHT GAIN and severe SEDATION
Risperidone: Extrapyramidal side effects (dose dependent), weight gain
Quetiapine: weight gain
