Pharmacology

Question 1

Why are newer atypical anti psychotics associated with a lower risk of extra pyramidal side effects (EPSE)?

Answer 1

Atypical anti-psychotics act as antagonists @ the 5HT-2A serotonin receptor. This leads to downstream effects that cause an increase in dopamine within the nigrostriatal pathway. This reduces the likelihood of a dopamine deficiency in the nigrostriatal pathway (which causes EPSEs).

Question 2

What are long-acting injectable anti psychotics?

Answer 2

AKA ‘depots’
Given via long-acting IM injection rather than oral
Beneficial for pt with poor oral compliance
Loss of insight may be a problem for tx

However, not all oral tablets are available

A mixture of typical and atypical anti psychotics are available: zuclopethixol, flupentixol, haloperidol, olanzapine, paliperidone, ariprazole

Question 3

What are the Sx of SSRI discontinuation syndrome?

Answer 3

• flu-like
• sudden return of anxiety or depression
• Increased mood change
• Restlessness
• Difficulty sleeping
• Unsteadiness
• Sweating
• GI SX: pain, cramping, diarrhoea, vomiting
• Paraesthesia

Question 4

What are some common drug-drug interactions with SSRIs?

Answer 4

NSAIDs - must offer PPI
Warfarin/heparin - avoid SSRIs and offer mirtazapine instead
Triptans - increased risk of serotonin syndrome
Monoamine oxidase inhibitors - increased risk of serotonin syndrome
Aspirin

Question 5

How long should we take to discontinue an SSRI?

Answer 5

Should be gradually reduced over a 4 week period (not necessary with fluoxetine? Paroxetine has a higher incidence of discontinuation sx)

Question 6

Regarding SSRI use in pregnancy, what is recommedned?

Answer 6

Benefits and risks must be weighed up - involve seniors and experts.
1st trimester - increased risk of congenital heart defects i.e. paroxetine
3rd trimester - persistent pulmonary hypertension of newborn

Question 7

What are the features of serotonin syndrome?

Answer 7

Autonomic instability - tachycardia, hyperthermia
Neuromuscular hyperreactivity - restlessness
Mental status changes - confusion

Question 8

What are the side effects of SSRIs?

Answer 8

GI upset
Anxiety and agitation
QT interval prolongation (especially associated with citalopram)
Sexual dysfunction - i.e. erectile dysfunction
Hyponatreamia
Gastric Ulcer

Question 9

What is treatment resistant schizophrenia (not responded to consecutive trials of 2 antibiotics) treated with?

Answer 9

Clozapine

Question 10

What side effects are associated with tricyclic antidepressants?

Answer 10

Urinary retention
Drowsiness
Blurred vision
Constipation
Dry mouth
(Anti-cholinergic activity)

Question 11

What are the psychological side effects of chlorphenamine (antihistamine)?

Answer 11

Anti-depressant/anxiety effects

In the elderly: Increased risk of acute delirium, dry mouth and urinary retention