Antidepressants Flashcards
What do SSRIs stand for?
Selective serotonin reuptake inhibitors
What are some examples of SSRIs?
- Sertraline
- Fluoxetine
- Paroxetine
- Citalopram
- Escitalopram
- Fluvoxamine
How do SSRIs work?
They inhibit the re-uptake of serotonin meaning more serotonin is available to pass their messages between nearby nerve cells.
How long does it take for SSRIs to be effective?
2-4 weeks
Which SSRI is preferred post MI?
Sertraline- more evidence for being safer than other antidepressants
Which SSRI is the choice of drug when antidepressants are indicated in children/ adolescents?
Fluoxetine
Which SSRIs have a higher propensity for drug interactions?
- Fluoxetine
- Paroxetine
What is the most common side effect of SSRIs?
GI symptoms
What should be prescribed to patients on an SSRI and NSAID?
And why?
A PPI should be prescribed
Due to increased risk of GI bleeding
What is a side effect of using citalopram?
Prolonged QT interval
Therefore shouldn’t be used in those with long QT syndrome, now pre-existing QT interval prolongation or in combination with other medications that prolong QT interval
What are some common drugs that interact with SSRIs?
- NSAIDS: co-prescribe PPI
- Warfarin/heparin/aspirin : consider using mirtazapine instead
- Triptans: Increased risk of serotonin syndrome
- Monoamine oxidase inhibitors (MAOIs): Increased risk of serotonin syndrome
Following initiation of antidepressant therapy , when should patients be reviewed?
Normally: after 2 weeks
<25 years/ increased risk of suicide: after 1 week
For how long should patients continue antidepressant therapy?
For at least 6 months after remission as it reduces risk of relapse
How should SSRIs be stopped?
Reduced gradually over a 4 week period
What discontinuation symptoms can SSRIs cause?
MAIN ONES:
- GI problems: Diarrhoea, vomiting, cramping, pain
OTHER:
- Increased mood change
- Restlessness
- Difficulty sleeping
- Unsteadiness
- Sweating
- Paraesthesia
What is a potential risk of using SSRIs in the first trimester of pregnancy?
Small increased risk of congenital heart defects
What is a potential risk of using SSRIs in the third trimester of pregnancy?
Can result in persistent pulmonary hypertension of the newborn
Which SSRI is associated with the most risk in pregnancy?
Paroxetine- increased risk of congenital malformation particularly in the first trimester
What electrolyte imbalance can SSRIs cause?
Hyponatraemia
What are SNRIs?
Serotonin and noradrenaline re-uptake inhibitors
How do SNRIs work?
They inhibit the re-uptake of serotonin and noradrenaline= increased concentrations in synaptic cleft = happy vibes
What are some examples of SNRIs?
- Venlafaxine
- Duloxetine
What may need to be monitored at high doses of SNRIs?
Blood pressure - can cause HTN
What type of antidepressant is Mirtazepine?
Norepinephrine and specific serotonergic antidepressant (NaSSA)
What are some side effects of Mirtazepine?
COMMON:
- Sedation
- Increased appetite/ weight gain
{Can be good for patients who are struggling with sleep and eating}
LESS COMMON:
- Jaundice/ LFT changes
- Postural hypotension
- Blood dyscrasias
What are some examples of tricyclic antidepressants (TCAs)
- Amitriptyline
- Clomipramine
- Dothiepin
- Imipramine
- Lofepramine
What are TCAs most commonly used for?
Less commonly used for depression due to side-effects and toxicity in overdose
Widely used in the treatment of neuropathic pain where smaller doses are typically required
What are come common side effects of TCAs?
- Drowsiness
- Dry mouth
- Blurred vision
- Constipation
- Urinary retention
- Lengthening of QT interval
Which TCAs are considered most dangerous in overdose?
Amitriptyline and Dosulepin (Dothiepin)
What is the most common use of low dose amitriptyline?
Management of neuropathic pain
Prophylaxis of headache (tension and migraine)
Which TCAs are sedative?
MORE SEDATIVE:
- Amitriptyline
- Clomipramine
- Dosulepin
- Trazodone (technically a tricyclic related antidepressant)
LESS SEDATIVE:
- Imipramine
- Lofepramine
- Nortriptyline
What are some early features associated with TCA overdose?
Anticholinergic properties:
- Dry mouth
- Dilated pupils
- Agitation
- Sinus tachycardia
- Blurred vision
What are some features of severe TCA poisioning?
- Arrhythmias
- Seizures
- Metabolic acidosis
- Coma
What are some ECG changes seen in TCA overdose?
- Sinus tachycardia
- Widening of QRS
- Prolongation of QT interval
QRS widening in TCA overdose can cause what?
Widening of QRS > 100ms = increased risk of seizures
Widening of QRS > 160ms = increased risk of ventricular arrhythmias
What is the treatment for TCA overdose?
IV bicarbonate:
- first line therapy for hypotension or arrhythmias
- indications include widening of QRS interval >100ms / ventricular arrhythmias
IV liquid emulsion is increasingly used to bind free drug and reduce toxicity
What are some examples of monoamine oxidase inhibitors (MAOIs)?
- tranylcypromine
- phenelzine
- moclobemide
- isocarboxazid
What does monoamine oxidase do?
Serotonin and noradrenaline are metabolised by monoamine oxidase in the presynaptic cell
What are MAOIs used for?
In the treatment of atypical depression (e.g. hyperphagia) and other psychiatric disorder
What are some side effects of non-selective MAOIs?
- Hypertensive reactions
- Anticholinergic effects
What foods should be avoided when on MAOIs?
Tyramine containing foods e.g:
- Cheese
- Pickled herring
- Bovril
- Oxo
- Marmite
- Broad beans
{Can cause hypertensive crisis}
What is the first line treatment for depression?
SSRIs
What is the first line SSRI for anxiety?
Sertraline
What should be offered if the first line treatment for anxiety is ineffective?
If sertraline is ineffective:
- offer an alternative SSRI or SNRI (e.g. duloxetine and venlafaxine)
If SSRIs/ SNRIs not tolerated:
- offer pregabalin
What should be trialled for panic disorder if first line treatment contraindicated/ ineffective?
If SSRI are contraindicated/ no response after 12 weeks try:
imipramine or clomipramine
What medication can be used in OCD with moderate/ severe functional impairment?
- SSRI
- Clomipraine if :preference/ previous good response/ if SSRI contraindiated
What can cause serotonin syndrome?
- MAOIs
- SSRIs:
* St John’s Wort can interact with SSRI to cause serotonin syndrome
*Tramadol may also interact with SSRIs - Ecstasy
- Amphetamines
What are the symptoms of serotonin syndrome?
Neuromuscular excitation:
- Hyperreflexia (* increased reflexes*)
- Myoclonus
- Rigidity
Autonomic nervous system excitation:
- Hyperthermia
- Sweating
Altered mental state:
- Confusion
What is the management for serotonin syndrome?
- Withdrawal of medication
- IV fluids
- Benzodiazepines
In more severe cases:
- Cyproheptadine
- Chlorpromazine
{serotonin antagonists}
What are the first line drugs in PTSD?
Venlafaxine/ SSRI
