Psychiatric Drugs Tutorial Flashcards

1
Q

What are the common Adrenergic/Noradrenergic side effects ?

A

Sweating
Tremor
Headaches
Nausea
Dizziness

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2
Q

What are the common Muscarinic side effects ?

A

Dry mouth, difficulty swallowing, thirst
Difficulty urinating, urinary retention
Hot and flushed skin
Dry skin

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3
Q

What are the common histamine side effects ?

A

Dry mouth
Drowsiness
Dizziness
Nausea and vomiting

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4
Q

How do antidepressants work?

A

Most work on serotonin activity and aim to increase activity at post synaptic receptors
Most have most of their effect in two to three weeks

Types include:
SSRIs, SNRIs, Mirtazapine, Tricyclics, MAOIs

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5
Q

How do SSRIs work?

A

Increase serotonin activity by reducing the presynaptic reuptake of serotonin after release
= more serotonin sits in the synapse

Leads to a down regulation of post-synaptic receptors

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6
Q

Side effects of SSRIs?

A

Sense of restlessness, agitation on initiation (countered by judicious use of benzodiazepines)
Nausea, GI disturbance
Headache
Weight changes
Sexual dysfunction - tends to be more enduring

Less common – bleeding and suicidal ideation (age related)

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7
Q

Give 4 common SSRIs and the key things to look out for when prescribing them

A

Sertraline (50 to 200mgs) – safest in cardiac disease, useful because incidence of depression is higher in people post-MI than with other admissions

Citalopram (20 to 40mgs)/Escitalopram (10 – 20mgs) – watch out for QTc prolongation

Fluoxetine (20 to 60mgs) – watch out for serotonin syndrome when switching

Paroxetine (20 to 60mgs) – watch out for discontinuation syndrome

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8
Q

What is the value at which the QTc is prolonged?

A

450 msec for men and 470 msec for women

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9
Q

How do SNRIs work? Common side effects?

A

Act in the same way as SSRI’s but bind to noradrenaline reuptake receptors as well.

evidence base for use in neuropathic pain

Side effects similar to SSRIs but greater potential for sedation, nausea and sexual dysfunction

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10
Q

Give 2 SNRIs and their dose

A

Duloxetine (60 to 120mgs): low dose range

Venlafaxine (75 to 375mgs): greater efficacy and can go to a higher dose
Caution with higher doses in heart disease – monitor blood pressure at doses above 225mgs.

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11
Q

Why might suicidal ideation go up when starting antidepressant treatment?

A

Energy levels and motivation may improve before other symptoms
May be more likely to act on existing suicidal thoughts

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12
Q

How does Mirtazipine work?

A

Unique class : acts as a 5HT-2 and 5HT-3 antagonist

Strong H1 (histamine) activity – hence sedation

Major side-effects are sedation and weight gain which can be used to therapeutic advantage

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13
Q

Indications for tricyclic antidepressants? Key side effects?

A

useful for those who do not respond to SSRI’s, also used at low doses for neuropathic pain

Newer tricyclics (such as lofepramine and and nortriptyline) tolerated better than older tricyclics (amitriptyline)
All tricyclics have the potential to cause muscarinic and histaminic side effects
Can be fatal in overdose – cause QTc prolongation and arrhythmias

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14
Q

What are the different categories of monoamine oxidase B inhibitors?

A

MAOI – A (work more on serotonin) and MAOI – B (work more on dopamine) - all can potentially increase adrenaline

Irreversible – more dangerous: Phenelzine; Isocarboxazid
Reversible – less dangerous: Moclobamide; Tranylcypromine

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15
Q

Key things to know about MAOIs?

A

Potential for significant and dangerous interaction with other drugs

Potential for tyramine reaction leading to hypertensive crisis – avoid cheese, pickled meats, wine and other tyramine products

If changing to another antidepressant need a washout period (up to 6 weeks)

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16
Q

What should you consider when deciding which antidepressant to prescribe?

A

What has been used before?
Was it effective and/or tolerated?

Are there particular symptoms or comorbidities you may want to address?
* Weight loss
* Insomnia
* Neuropathic pain

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17
Q

What antidepressants are generally prescribed to someone on first presentation?

A

In new cases with no previous treatment start with an SSRI unless:
there is major weight loss or major sleep difficulty, in which case consider Mirtazapine OR comorbid neuropathic pain, in which case consider an SNRI

In most cases start with an SSRI (usually sertraline), if no effect switch to a different SSRI, if no effect switch to SNRI, Venlafaxine or Mirtazapine

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18
Q

How do you decide whether to increase the dose of an antidepressant or switch the drug?

A

For depression: if an antidepressant has absolutely no benefit at atypical dose it’s not worth increasing the dose – switch. If partial benefit increase the dose.

For anxiety (especially OCD): consider increasing dose if no initial benefit.

If an antidepressant has significant side-effects these may get better in a couple of weeks but if they cause a big problem for the patient – switch.

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19
Q

What features can discontinuation syndrome present with?

A

sweating, shakes, agitation, insomnia, headaches, irritability, nausea and vomiting, paraesthesia, clonus

The shorter the half-life the bigger the problem, Paroxetine and Venlafaxine often hardest to stop

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20
Q

Discontinuation syndrome is more likely to occur:

A

in drugs with a short half life

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21
Q

How can you reduce risk of discontinuation syndrome?

A

Go slow!
Can alternate days of taking and not taking or snap tablets in half (better option)
Sometimes worth switching to Fluoxetine (very long half-life) and then reducing the Fluoxetine

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22
Q

What is Vortioxetine?

A

new antidepressant with all sorts of serotonergic activity (differs according to receptor)

Effective
Well tolerated – most common side effect is nausea (but less severe than Venlafaxine)

Evidence for improvement in difficult to treat cognitive symptoms

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23
Q

Serotonin syndrome occurs when there is an increase in systemic serotonin, sometimes due to switching antidepressants and 2 being present in the system at the same time (e.g. fluoxetine and one other), or due to increasing the antidepressant dose.

How does serotonin syndrome present? Mx?

A

Cognitive – headaches, agitation, hypomania, confusion, coma

Autonomic – shivering, sweating, hyperthermia, tachycardia, nausea and diarrhoea

Somatic – myoclonus, hyperreflexia and tremor

Treatment usually supportive: fluids and monitoring

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24
Q

What is the MOA of antipsychotics? General side effects?

A

Also called neuroleptics

All current antipsychotics reduce level of dopamine activity at D2 receptors, target dopaminergic pathways in the brain are mesocortical and mesolimbic (psychosis = increased dopamine, parkinsonism = decreased dopamine)

All antipsychotics have potential for sedation, extrapyramidal side effects and weight gain
All antipsychotics can cause acute dystonia, including oculogyric crisis

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25
Q

What is the difference between typical and atypical antipsychotics?

A

Typical older and more likely to cause extra-pyramidal side effects – remember this difference!!!

Typical tend to bind more to muscarinic and histaminic receptors
Atypical tend to have more serotonergic activity

26
Q

Give some typical antipsychotics

A

Haloperidol
Flupenthixol
Zuclopenthixol
Chlorpromazine
Sulpiride

27
Q

Give some atypical antipsychotics

A

also called Second Generation Antipsychotics: SGAs

Clozapine, Olanzapine, Risperidone, Quetiapine, Amisulpiride, Aripiprazole – D2 partial agonist (not antagonist) fewer side effects

28
Q

Side effects of antipsychotics?

A

Typical - more likely to cause:
Extra-Pyramidal Side Effects
Dizziness
Sexual dysfunction

Atypical - more likely to cause:
Weight gain
Dyslipidaemia and diabetes

29
Q

How should patients on antipsychotics be monitored?

A

Baseline: FBC; Lipids; LFT; HbA1C. Weight. ECG. Blood pressure and pulse

Weekly: Weight in an ideal world

Three months: FBC; Lipids; LFT; HbA1C. Weight. ECG. Blood pressure and pulse

Yearly: FBC; Lipids; LFT; HbA1C. Weight. ECG. Blood pressure and pulse

30
Q

What is neuroleptic malignant syndrome?

A

Rare, life-threatening reaction to antipsychotics
* Fever, confusion, muscle rigidity, sweating, autonomic instability

Death usually due to:
* Rhabdomyolysis, renal failure, seizures

31
Q

Risk factors for neuroleptic malignant syndrome?

A

High potency dopamine antagonists (typical antipsychotics) in antipsychotic naive, high doses, young men

32
Q

What tests might you do to confirm dx of NMS?

A

WCC (rule out sepsis), CRP, Creatinine Kinase (rhabdomyolysis)

33
Q

How can neuroleptic malignant syndrome be managed?

A

Emergency referral to A&E
Stop antipsychotics, give benzos for acute behavioural disturbance
Fluid resuscitation
Reduce temperature (cooling blankets)
Oxygen if necessary

  • Rhabdomyolsis – fluids and sodium bicarbonate – alkalise the urine
  • Relax muscles – first line: dantrolene or lorazepam; second line bromocriptine
34
Q

Why do you give anticholinergics to treat EPSEs which are due to a decrease in dopamine?

A

ratio of dopamine: acetylcholine in nigrostriatal pathway is more important that absolute quantities

if there is too much acetylcholine in relation to dopamine, sometimes it is easier to decrease acetylcholine than increase dopamine

35
Q

What anticholinergic is commonly used to treat extra-pyramidal side effects?

A

Procyclidine

potential for misuse, not effective for (and may exacerbate) tardive dyskinesia

36
Q

What are acute dystonias?

A

Sustained, often painful, muscular spasms, producing twisted abnormal postures.

50% cases in first 48 hours; 90% in first 5 days

Most common: neck; tongue; jaw; oculogyric crisis (neck arched and eyes rolled back)

37
Q

How should acute dystonias be managed?

A

Stop antipsychotic

Administer IM or IV anticholinergics – first line is procyclidine

Continue for 1 to 2 days after dystonia and consider long-term prophylactic

38
Q

MOA of clozapine?

A

atypical antipsychotic

D2 antagonist; 5HT-2 antagonist
Most efficacious antipsychotic ever!
Improvements can continue for several months

39
Q

Clozapine should be used in schizophrenia after two other antipsychotics have not been effective.

What are the dangerous side effects? How should it be monitored?

A

Significant potential for agranulocytosis (severe leukopenia): therefore close monitoring of FBC: weekly for first 18 weeks, then fortnightly for up to a year, then monthly

Significant potential for gastrointestinal hypo-mobility: constipation, potentially fatal bowel obstruction

Other side-effects include hypersalivation and urinary incontinence

Dose titrated slowly upward over two weeks and vital signs monitored due to potential for autonomic dysregulation

40
Q

How should agranulocytosis due to clozapine be managed?

A

Stop Clozapine
Stop any other potentially marrow supressing drugs – e.g. Sodium Valproate
Avoid other antipsychotics for a couple of weeks where possible, though if needed Aripiprazole has less potential for bone marrow suppression

Contact Consultant Haematologist as an emergency

Avoid sources of infection and consider prophylactic broad-spectrum abx

Sometimes lithium is used to increased WCC and neutrophil count, Granulocyte colony-stimulating factor (G-CSF) has been used

41
Q

Purpose of olanzapine clinic?

A

patients need to stay in hospital and be monitored for 3 hours after injection because of risk of tachycardia and hypotension if it enters the blood stream too quickly (generally small spheres pop and cause the drug to steadily enter the circulation over the next few hours but this can go wrong)

42
Q

Purpose of clozapine clinic?

A

Ensure FBC carried out before dose is given

43
Q

EPSEs are due to:

A

dopamine antagonism in the nigrostriatal pathway

44
Q

The 3 most common antipsychotic side effects reported by patients are:

A

weight gain, akathisia and sedation

45
Q

Most appropriate administration route for an inpatient refusing to take their antipsychotic tablet?

A

long-acting depot injection

46
Q

What are the 4 main anxiolytics?

A

Beta-blockers
Benzodiazepines
Pregabalin
Antidepressants

47
Q

Beta blockers act by reducing autonomic nervous system activation to help with bio-psycho-feedback (less physical symptoms like tachycardia = less exacerbation of anxiety).

Which is the most commonly used in psychiatry? Contraindication?

A

propanolol- dangerous in overdose

contraindicated in asthma, limited efficacy for enduring anxiety disorders

48
Q

What is the MOA of benzodiazepines?

A

Most typically used are diazepam (long half-life) and lorazepam (shorter half-life)

Bind to GABA receptors to potentiate the effect of GABA and therefore reduce the excitability of neurones.

= positive allosteric modulators of GABA receptor

49
Q

What are the problems with benzos?

A

Significant potential for tolerance and dependence
Significant potential for misuse
Use very cautiously and for no more than six weeks

Occasionally cause paradoxical disinhibition

50
Q

MOA of pregabalin?

A

Binds to voltage gated calcium channels on neurones
Reduces neuronal activity (i.e. is a CNS depressant)

Used in anxiety, neuropathic pain and epilepsy
Aim for short term use

51
Q

Side effects of pregabalin?

A

Can cause sedation and weight gain

52
Q

What are the categories of hypnotics (sleeping tablets)?

A

Benzodiazepines:
* Temazepam, Lormatazepam, Nitrazepam

Nonbenzodiazepines: usually favoured
* Act in a very similar way (positive allosteric modulators) , also called Z drugs
* Zopiclone, Zolpidem

53
Q

What are the problems with hypnotics?

A

Significant potential for misuse, dependence, rebound insomnia.

Use for only two weeks and take for only 5 out of 7 days each week to reduce potential for tolerance

54
Q

Mood stabilisers are used to treat bipolar disorder. What groups are available?

A

Lithium
Anticonvulsants
Second Generation (Atypical) Antipsychotics

55
Q

Lithium is one of the most effective mood stabilisers with an unknown mechanism of action.
What are the benefits? What is the risk?

A

Significant evidence that lithium reduces suicide – and it has a licence for reduction of self-harm
Also used to augment antidepressants

Narrow therapeutic window (gap between effective dose and toxic dose)
requirement for regular serum lithium levels – weekly after dose change until level stable then 3 monthly once stable

56
Q

Side effects of lithium?

A

GI disturbance (especially on initiation), metallic taste and/or dry mouth, fine tremor, polydipsia and polyuria, weight gain

57
Q

Long term effects of lithium?

A

Hypothyroidism – usually reversible
Renal impairment (entirely excreted by the kidneys) – usually irreversible (and occurs most at above therapeutic doses)
Therefore annual U&Es and TFTs

58
Q

How does lithium toxicity present?
How is it managed?
What increases the risk?

A

Confusion, coarse tremor, nausea and vomiting, ataxia and seizures

Treatment:
Stop lithium, supportive measures – IV fluid, dialysis if necessary, benzodiazepines for seizures

Potential for toxicity increases with dehydration – advise to drink lots of water in hot climates

Interactions that can increase levels dangerously include: NSAIDS, Loop diuretics, ACE inhibitors

59
Q

What is the first line drug for bipolar?

A

Quetiapine - SGA

60
Q

Most common anticonvulsants in bipolar are:

A

Sodium Valproate – avoid in women of child bearing age due to teratogenicity, check LFTs before and soon after starting

Carbamazepine

Lamotrigine – potential for Stevens Johnson Syndrome

61
Q

Problems with anticonvulsants?

A

Most anticonvulsants have potential to cause thrombocytopenia so check FBC

Side effects include sedation and weight gain

62
Q

What drugs can be used in ADHD? How should they be monitored in kids?

A

CNS stimulants- hyperactivity is a stimulating behaviour
* Methylphenidate – most commonly prescribed, often given with a combination of immediate and sustained release (in the same tablet)
* Dextroamphetamine

Monitor weight, height (in children) and pulse