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Flashcards in Antidepressants Deck (55)
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1
Q

What medications are associated with prolonged QTc?

A
TCAs
Lithium
SSRIs
Venlafaxine (SNRI)
Macrolides e.g. erythromycin and clarithromycin
Sotalol
Methadone
2
Q

Name the different types of antidepressants

A
MAOIs
TCAs
SSRIs
SNRIs
NaSSA - NA and specific serotonergic antidepressant
(Lithium)
3
Q

Which patient groups should you be more cautious with prescribing antidepressants?

A
Renal or hepatic impairment - excretion and metabolism
Cardiac problems - prolong QTc
Epilepsy - increased risk of seizures
Pregnant or breastfeeding
Elderly or children
4
Q

How should antidepressant switching occur?

A

Cross-tapering: reduction of old antidepressant whilst increasing the new antidepressant.

Aim is to minimise the fluctuation of serum antidepressant levels to reduce the risk of side effects and behavioural changes.

5
Q

Name 2 MAOIs

A

Isocarboxazid

Phenelzine

6
Q

Describe the mechanisms of action of MAOIs

A

Irreversible inhibition of MAO-A and MAO-B ➔ accumulation of monoamines (particularly dopamine and serotonin) in the synaptic cleft

7
Q

Why has Phenelzine been discontinued?

A

‘Cheese reaction’
Hypertensive crisis due to accumulation of tyramine which is found in cheese, wine, and other foods.

Avoid indirect sympathomimetics.

8
Q

Name 3 side effects of MAOIs

A
Risk of hypertensive crisis
Postural hypotension and dizziness
Euphoria
Antimuscarinic effects
Hepatotoxicity
Insomnia
Anxiety
9
Q

List 2 cautions for MAOIs

A

Poorly controlled hypertension

Hyperthyroidism

10
Q

List 2 contraindications for MAOIs

A

Pheochromocytoma

Stroke

11
Q

What should be monitored if taking a MAOI?

A

Blood pressure - postural hypotension and HTN crisis

12
Q

Name 2 TCAs

A

Amitriptyline - also used for neuropathic pain
Clomipramine - 2nd line OCD Tx
Imipramine
Trimipramine

13
Q

Describe the mechanism of action of TCAs

A

Serotonin and NA reuptake inhibition

14
Q

Name 3 side effects of TCAs

A
Sedation
Impaired psychomotor function
Antimuscarinic effects
CVS: tachycardia, postural hypotension, prolonged QTc sudden cardiac death
Lowers seizure threshold
Weight gain
15
Q

Why is TCA toxicity dangerous?

A

TCAs are cardiotoxic in overdose.

Most: Amitriptyline
Least: Lofepramine

16
Q

What monitoring is advised when taking TCAs?

A

Cardiac and liver function

Longterm: U&Es, FBC, weight

17
Q

Name 3 SSRIs

A

Sertraline
Fluoxetine
Paroxetine
Citalopram - prolongs QTc

18
Q

Describe the mechanism of action of SSRIs

A

Inhibit the reuptake of serotonin ➔ accumulation in the synaptic cleft

19
Q

Name 3 side effects of SSRIs

A
Nausea
GI upset
Agitation - early onset
Sexual dysfunction
Anorexia
Vivid dreaming
Prolonged QTc
SIADH ➔ dilution hyponatraemia

Rare: Mania, increased suicidal ideation and self-harm (under 30s), EPSP

20
Q

What are the extrapyramidal side effects?

A

Akathisia - restlessness
Tardive dyskinesia - involuntary twisting of facial muscles, late onset, can involve extremities (hands > feet)
Acute dyskinesias and dystonic reactions
Parkinsonism - rigidity, pill rolling tremor, bradykinesia
Akinesia

21
Q

What is neuroleptic malignant syndrome?

A

Life-threatening reaction (10% mortality) in response to neuroleptic medication (within 1 month of starting).

Characterised by tetrad of: fever*, muscle rigidity, altered mental state, and autonomic dysfunction. Typically develops over a few days.

Tx: stop causative drug + ICU care

22
Q

What is the consequence of SSRI toxicity

A

Serotonin syndrome:

Restlessness, XS sweating, tremor, shivering, myoclonus, confusion, convulsions, death

23
Q

Which SSRI has the highest risk of Serotonin syndrome and why?

A

Paroxetine due to its short half life.

24
Q

What should be monitored when taking SSRIs?

A

Risk of suicide, as SSRIs can increase the risk.

25
Q

Name 2 SNRIs

A

Venlafaxine

Duloxetine

26
Q

Describe the mechanism of action of SNRIs

A

Inhibits reuptake of serotonin and noradrenaline

27
Q

Name 3 side effects of SNRIs

A

Same SE as SSRIs: Nausea, GI upset, sexual dysfunction, anorexia, vivid dreams, prolonged QTc

Additional: Sleep disturbances, hypertension, dry mouth, hyponatraemia

28
Q

What are the indications for Duloxetine?

A

Major depression
GAD
Diabetic neuropathy
Stress urinary incontinence (moderate-severe)

29
Q

What are the indications for Venlafaxine?

A

Major depression
GAD
Social phobia

30
Q

What are the indications for Sertraline?

A

Depression
OCD
Panic disorder, PTSD, Social phobia

31
Q

What are the indications for Fluoxetine?

A

Major depression
Bulimia nervosa
OCD

32
Q

What are the indications for Paroxetine?

A

Major depression
OCD
Social phobia, PTSD, GAD, Panic disorder

33
Q

What are the indications for Citalopram?

A

Depression

Panic disorder

34
Q

Name 1 NaSSa

A

Mirtazapine

35
Q

What are the indications for Mirtazapine?

A

Major depression

PTSD

36
Q

Describe the mechanism of action for NaSSa

A

5-HT and alpha receptor antagonist

*Mirtazapine also blocks histamine receptors

37
Q

Name 3 side effects of NaSSa

A

Common: Sedation (greater at lower dose)
Increased appetite and weight gain

Uncommon: Transaminase elevation, jaundice, postural hypotension, closed angle glaucoma

Rare: Agranulocytosis

38
Q

Name 2 contraindications of NaSSa

A

Renal impairment
Hepatic impairment
Jaundice
Pregnancy

39
Q

What is the benefit of Mirtazapine’s mechanism of action?

A

It differs from other antidepressant mechanisms. Therefore it can be used in combination with SSRIs or Venlafaxine, without increasing the risk of serotonin syndrome.

40
Q

Which situation would most benefit from the action and side effects of Mirtazepine?

A

Depression with insomnia - sedation side effect

Depressive reduced appetite - weight gain and increased appetite side effect

41
Q

Which medication is used for treatment-resistant depression?

A

Lithium

42
Q

What are the indications of Lithium?

A

Treatment resistant depression (Tx and prophylaxis)
Bipolar affective disorder (gold standard Tx)
Mania (Tx and prophylaxis)
Aggressive or self-harming behaviour

43
Q

What property of Lithium is especially useful in depression?

A

Lithium decreases suicidal ideation

44
Q

List 3 side effects of Lithium

A

NaV
GI disturbances - diarrhoea
Fine tremor
Diabetes insipidius - polyuria and polydipsia
Weight gain
Thyroid problems (Female 8:1)
Teratogenic - Ebstein’s anomaly (cardiac)
Mild renal impairment ➔ risk of chronic renal failure

45
Q

Describe the presentation of Lithium toxicity

A
Seizures
Dysarthria
Reduced consciousness, coma
Ataxia
Coarse tremor
Acute kidney injury
46
Q

What ECG changes are seen with Lithium?

A

Flattened T wave
Wide QRS
Prolonged QTc

47
Q

What drugs increase lithium plasma concentration?

A
ACEi/ARBs
NSAIDs
SSRIs and other antidepressants
Diuretics (and dehydration)
Haloperidol and other antipsychotics
48
Q

What drugs decrease lithium plasma concentration?

A

Antacids - neutralise stomach acid

Theophylline - COPD and Asthma

49
Q

What is the DDI between SSRIs and NSAIDs?

A

Increased risk of GI bleed.

If using both, give a PPI.

50
Q

Which TCA has the highest risk of antimuscarinic side effects?

A

Imipramine

51
Q

Which SSRI is first line treatment for children and adolescents?

A

Fluoxetine

52
Q

What monitoring is required when taking Lithium?

A

Blood monitoring taken 12h after each dose change
ECG
TFT (6 monthly)
U&E (6 monthly)

53
Q

How long should antidepressants be continued once depression (1st episode) has enter remission?

A

Continue for 6 months after remission

54
Q

How long should antidepressants be continued once depression (2nd episode) has enter remission?

A

Continue for 2 years after remission

55
Q

What is the effect of hyponatraemia on lithium?

A

Hyponatraemia can reduce renal excretion of lithium -> increased risk of lithium toxicity