Drugs in Psych

Question 1

Explain the mechanism of action, adverse effects and examples of typical antipsychotics

Answer 1

MoA - Dopamine D2 receptor anatagonist.
Adverse effects - Extrapyramidal side effects and hyperprolactinaemia.
Examples - Haloperidole or chlorpromazine.

Question 2

Explain the mechanism of action, adverse effects and examples of atypical antipsychotics

Answer 2

MoA - Variety of receptors - D2, D3, D4, 5-HT.
Side effects - extrapyramidal side effects, hyperprolactinaemia, metabolic side effects.
Examples - Clozapine, risperidone, olanzapine.

Question 3

What are examples of extrapyramidal side effects?

Answer 3

Parkinsonism,
Acute dystonia - sustained muscle contraction (managed with procyclidine)
Akathisia (restlessness),
Tardive dyskinesia (chewing and pouting, abnormal, involuntary movements)

Question 4

Risks of using antipsychotics in elderly patients?

Answer 4

Increased risk of stroke and increased risk of VTE

Question 5

Other side effects (non extrapyramidal)

Answer 5

Antimuscarinic (dry mouth, blurred vision, constipation, urinary retention).
Sedation,
Weight gain,
Raised prolactin,
Impaired glucose tolerance,
Neuroleptic malignant syndrome,
Reduced seizure threshold,
Prolonged QT interval (particular haloperidol)

Question 6

Monitoring for antipsychotics

Answer 6

FBC, U&Es and LFTs
Lipids and weight,
Fasting blood glucose and prolactin,
BP
ECG (baseline)
CV risk assessment

Question 7

Main adverse effects of atypical antipsychotics?

Answer 7

Weight gain,
Clozapine - agrangulocytosis,
Hyperprolactinaemia.

Question 8

Examples of atypical antipsychotics

Answer 8

clozapine
olanzapine: higher risk of dyslipidemia and obesity
risperidone
quetiapine
amisulpride
aripiprazole: generally good side-effect profile, particularly for prolactin elevation

Question 9

How should patients withdraw from benzodiazepines

Answer 9

Reduce by 1/8th of the daily dose every 2 weeks. If experiencing difficulty with this then switch to equivalent dose of diazepam and then reduce dose of diazepam by 2/2.5mg ever 2-3 weeks

Question 10

Symptoms of benzodiazepines withdrawal syndrome?

Answer 10

insomnia
irritability
anxiety
tremor
loss of appetite
tinnitus
perspiration
perceptual disturbances
seizures

Question 11

What are the adverse effects of clozapine?

Answer 11

Agranulocytosis,
Neutropenia,
Reduced seizure threshold,
Constipation,
Myocarditis,
Hypersalivation.
Dose adjustment needed is smoking

Question 12

Features of Mirtazepine?

Answer 12

Antidepressant which blocks alpha2-adrenergic receptors.
Fewer side effects so useful in older people.
Two main side effects - increased appetite and sedation.

Question 13

What are features of non-slective monoamine oxidase inhibitors?

Answer 13

Used in treatment of atypical depression and other psychiatric disorders.
Side effects - hypertensive reactions with tyramine containing foods and anticholinergic effects

Question 14

What SSRI is most useful post MI?

Answer 14

Sertraline

Question 15

SSRI in children and adolescents?

Answer 15

Fluoxetine

Question 16

Adverse effects of SSRIs?

Answer 16

GI symptoms are most common.
Hyponatraemia
Increased risk of GI bleed.
May worsen anxiety and agitation

Question 17

Interactions with SSRIs?

Answer 17

NSAIDs (if needed then coprescribe a PPI)
Warfarin/heparin (if needed then consider using mirtazapine),
Aspirin,
Triptans (increased risk of serotonin syndrome)
MOAIs (increased risk of serotonin syndrome).

Question 18

Monitoring required with SSRIs?

Answer 18

Patients should be reviewed after two weeks unless under age 25 or at increased risk of suicide then these patients should be reviewed after 1 week.

If good response then patients should stay on treatment for 6 months after remission to prevent relapse

Question 19

How to withdraw from SSRIs and potential discontinuation symptoms?

Answer 19

Gradual reduce over 4 week period (not required with fluoxetine)
Discontinuation symptoms: Increased mood change, restlessness, difficulty sleepying, unsteadiness, sweating, GI symptoms (pain, cramping, diarrhoea, vomiting), paraesthesia

Question 20

SSRIs and pregnancy?

Answer 20

If used in first trimester there is increased risk of congenital heart defects.
If used in last trimester there is increased risk of persistent pulmonary hypertension.
Paroxetine has increased risk of congenital malformation.

Question 21

Features of SNRIs?

Answer 21

Examples - duloxetine and venlafaxine.
Used to treat major depressive disorders, generalised anxiety disorder, social anxiety disorder, panic disorders and menopause.

Question 22

What are the side effects of tricyclic antidepressants?

Answer 22

Drowsiness,
Dry mouth,
Blurred vision,
Constipation,
Urinary retention,
Postural hypotension,
Lengthening of QT inverval.