Psychiatric Drugs Flashcards
1
Q
Typical Antipsychotics
- What is their mechanism of action?
- What are their possible side effects?
- What 2 specific warnings are given when discussing in elderly patients?
- Give 2 examples.
A
- dopamine D2 receptor antagonists
- extra-pyramidal side effects
- parkinsonism: reduced facial expressions, tremor, shuffling gait
- akathisia: restlessness
- acute dystonia: sustained muscle contraction (e.g. torticollis, oculogyric crisis)
- tardive dyskinesia: repetitive, involuntary contractions of the tongue, muscles of the face and upper body
^someone is a wee tard for taking drugs
other
- antimuscarinic: dry mouth, blurred vision, urinary retention, constipation
- sedation, weight gain
- impaired glucose tolerance
- raised PRL (may result in galactorrhea, due to inhibition of dopaminergic tuberoinfundibulnar pathway)
- long QT interval
- neuroepilectic malignant syndrome
- reduced seizure threshold (bt worse in atypicals)
- increased risk of stroke
- increased risk of VTE
- haloperidol
- chlorpromazine
2
Q
How can the extra-pyramidal side effect of acute dystonia be managed
A
procyclidine
3
Q
Neuroepileptic malignant syndrome
- What clinical features can be seen?
- What is seen on investigation?
- How is it managed?
A
- hyperthermia
- muscle rigidity + bradykinesia
- altered mental status: agitation, confusion, stupor
- autonomic dysfunction: tachycardia, tachypnoea, dilated pupils, sweating
- raised WCC + CK
- withdraw medication
- cool the patient
- benzodiazepine + dantrolene
4
Q
Antipsychotics monitoring
What requires monitoring in antipsychotics and when?
A
- FBC, U+E, LFT: at start and then annually
- lipids + weight: at start, at 3 months, annually
- fasting glucose, PRL: at start, at 6 months, annually
- BP + ECG: at start (and BP frequently during dose titration)
- CV risk assessment: annually
5
Q
Atypical antipsychotics
- What is their mechanism of action?
- What are their main side effects?
- Give 3 examples.
A
- rich pharmacology possibly acting on D2, D3, D4 and 5-HT receptors
- weight gain -> type 2 diabetes -> metabolic syndrome
- hyperprolactinaemia (however not as common as in typical)
- clozapine
risperidone
olanzapine
6
Q
What antipsychotic would you lean towards if you desired the following:
- less sedating
- more sedating
- avoidance of weight gain
- safe with depot provera
A
- haloperidol, risperidone
- chlorpromazine, olanzapine
- haloperidol, aripiprazole
- risperidone
7
Q
Clozapine
- What type of drug is this?
- When is it particularly of use?
- What are its possible side effects?
- When might the patient’s dose need adjusted?
A
- atypical antipsychotic
- treatment resistant schizophrenia
- when had 6 week trials of 2 antipsychotics (at least one of which was atypical) which were not effective - agranulocytosis (very low WCC)
- neutropenia
- reduced seizure threshold
- constipation
- myocarditis
- hyper salivation
- if patient stops / starts smoking
8
Q
Benzodiazepines
- What is their mechanism of action?
- What can they be used for?
- Describe the advice given on how to withdraw a patient from benzodiazepine.
- State the symptoms of benzodiazepine withdrawal.
A
- enhances GABA inhibition by increasing the frequency of chloride channels
(barbiturates do so by in increasing the duration of chloride channels
- FREquently BENd, DURing BARBeque)
- sedation
- anxiolytic
- anticonvulsant
- muscle relaxant
- withdraw 1/8th (1/4-1/10) of dose every fortnight
if struggling, convert to same dose of diazepam and reduce by 2-2.5mg every 2-3 weeks - (similar to alcohol withdrawal)
- tremor
- irritability
- anxiety
- insomnia
- tinnitus
- sweating
- perceptual disturbances
- seizures
9
Q
How should you switch over the following antidepressants?
- citalopram, escitalopram, sertraline or paroxetine to another SSRI
- fluoxetine to another SSRI
- SSRI to TCA or SNRI
- fluoxetine to SNRI (e.g. venlafaxine) or TCA
A
- withdraw (slowly reduce dose) before starting new SSRI
- withdraw and then wait 4-7 days before starting new SSRI
- cross taper the drugs (slowly decrease old while simultaneously slowly increase new)
- withdraw fluoxetine and then wait 4-7 days before starting the new drug
NOTE: the differences seen between fluoxetine and other SSRIs is because of its longer half life
10
Q
ECT
- What is an absolute contraindication?
- What are the possible
a) short term side effects
b) long term side effects - How should SSRIs be managed?
- What are the indications for it?
A
- raised ICP
- a)
- headache
- nausea
- cardiac arrhythmia
- anterograde amnesia (short term memory loss following insult)
- retrograde amnesia (memory loss of events prior to ECT - much more commonly seen)
mnemonic - think of it as shocking out the memories
b) impaired memory
3. reduce daily dose (but not remove)
- severe depression (or moderate known to respond)
- manic episode
- life-threatening catatonia
11
Q
Lithium
- What are the possible side effects?
- a) what can happen in pregnancy?
b) how is this managed? - How are patients on lithium monitored?
NOTE: avoid taking NSAIDs while on lithium as can cause renal impatient
- > decrease in GFR
- > less lithium excreted
- > lithium toxicity
A
- tremor
- leucocytosis
- idiopathic intracranial hypertension
- GI upset
- thyroid enlargement (possibly leading to hypothyroid 6-18 months after initiation)
- hyperparathyroidism
- T wave flattening / inversion
- weight gain
- nephrotoxicity: nephrogenic diabetes insipidus leading to polyuria -> therefore thirst
- a) congenital heart defects
b) US scans at 8 and 18 weeks - lithium levels should be taken 12 hrs post dose
upon starting / changing dose levels should be monitored weekly until stable
once stable levels monitored 3 monthly
thyroid + renal function checked 6 monthly
12
Q
Mirtazapine
- What is its mechanism of action?
- When can it be particularly useful and why?
- When should it be taken?
A
- antidepressant blocking alpha2-adrenergic receptors
- in old people because it has fewer side effects
- > two side effects of increased appetite and sedation often even useful - at night as it is a sedative
13
Q
Monoamine oxidase inhibitors
- What is their mechanism of action
- When can they be used?
- What are their side effects?
A
- serotonin and noradrenalin are metabolised by monoamine oxidase in presynaptic cells (therefore these drugs inhibit that process)
- atypical depression
- other psychiatric disorders
- hypertensive reaction with tyramine based foods
(cheese, pickled herring, broad beans, oxo, bovril + marmite) - anticholinergic SEs
- hypertensive reaction with tyramine based foods
14
Q
SSRIs
- Which is the drug of choice
a) post MI
b) in children and adolescents - What action should you take with the following drugs?
a) NSAIDs
b) warfarin / heparin / aspirin - a) Which drugs when prescribed with SSRIs can cause an increased risk of serotonin syndrome?
b) What clinical features can be seen?
A
- a) sertraline
b) fluoxetine
2
a) avoid if possible - if very necessary prescribe PPI
b) avoid - try mirtazapine
3
a) Monoamine oxidase inhibitors, triptans
b)
- tachycardia + high BP
- restlessness / agitation / insomnia
- confusion
- headache
- muscle rigidity
+ symptoms often come on within hrs after taking drug
+ presence of fever indicates severe possibly causing seizure
15
Q
Stopping SSRIs
- How long should one take to withdraw them?
- a) What are the discontinuation symptoms?
b) Which drug is most likely to show these? - How long after a good response to antidepressant therapy should a patient keep taking the medication?
A
- 4 weeks (except not necessary for fluoxetine)
- a)
- increased mood change
- restlessness
- difficulty sleeping
- sweating
- GI upset (pain, diarrhoea, vomiting)
- paraethesia “electric-shock sensations”
b) paroxetine - another 6 months following remission of symptoms to reduce risk of relapse
