Antidepressants Flashcards
What psychiatric conditions are antidepressants indicated for?
(big long list)
Unipolar & bipolar depression
Organic mood disorders
Schizoaffective disorder
Anxiety disorders - OCD, panic, social phobia, PTSD
Premenstrual dysphoric disorder
Impulsivity associated with Personality disorders
How long (typically) does it take antidepressants to start working?
What is the course of action if an antidepressant does not have an effect?
Delay of 2-4 weeks after a therapeutic dose is achieved before symptoms improve
If no improvement in at least 2 months and dose has been titrated to the max - then switch to another antidepressant or augment with another agent
What are the classes of antidepressants?
SSRIs - Selective serotonin reuptake inhibitors
SNRIs - Serotonin/Noradrenaline reuptake inhibitors
TCAs - Tricyclic antidepressants
MAOIs - Monamine oxidase inhibitors
Novel agents
Tricyclic antidepressants (TCAs) are a class of antidepressant
What is their effect?
What are their benefits?
What are their negatives/risks?
Increase serotonin, dopamine, noradrenaline
Very effective but very toxic:
- Side effects (antihistaminic & anticholinergic)
- Lethal if overdosed
- Can cause QT lengthening on ECG at normal dose
What are some of the potential side effects of TCAs?
Antihistiminic & Anticholinergic effects:
- dry mouth
- drowsiness
- weight gain
- blurred vision
- constipation
- Long QT
What are the 2 types of TCAs?
Breifly describe the differences between them
Give examples of each
Tertiary & Secondary TCAs
Tertiary TCAs - eg amitriptyline, clomipramine:
- have amine side chains
- metabolised into desipramine, nortriptyline (2* TCAs)
- lots of side effects
Secondary TCAs - eg desipramine, nortriptyline:
- metabollites of tertiary TCAs
- same side effects but less severe
- primarily block NA
What are Monamine oxidase inhibitors (MAOIs) and how do they work?
What are they particularly good for treating?
Bind irreversibly to monoamine oxidase thereby preventing inactivation of amines such as - norepinephrine, dopamine & serotonin - leading to increased synaptic levels
Very effective for resistant depression
What are the side effects of Monamine oxidase inhibitors (MAOIs)?
Orthostatic hypotension - ie dizziness when standing up
Weight gain
Dry mouth
Sexual dysfunction
Sleep disturbance
Serotonin syndrome
What is a cheese reaction?
Hypertensive crisis can develop when MAOI’s are taken with:
1) tyramine-rich foods
* cheeses, red wine, fava beans, processed meats
2) sympathomimetics (sympathetic stimulant drugs)
What is serotonin syndrome?
Serotonin Syndrome can develop if take MAOIs with meds that increase serotonin or have sympathomimetic actions
Serotonin syndrome symptoms include:
- abdominal pain, diarrhoea
- sweats
- tachycardia & hypertension
- myoclonus
- irritability, delerium
can lead to hyperpyrexia, cardiovascular shock and death
How is serotonin syndrome avoided in the prescription of antidepressants?
Wait 2 weeks before switching from an SSRI to an MAOI
The exception of fluoxetine where need to wait 5 weeks because of long half-life
On the topic of SSRIs:
- a) how do they work?
- b) what are they used to treat?
- c) give some examples of SSRIs
a) Block presynaptic serotonin reuptake
b) SSRIs used to treat both depressive (usually first line) and anxiety symptoms
* they are activating so are esp good for hypersomnolence, fatigue etc
c) Fluoxetine, citalopram, sertraline
What are the side effects seen with SSRIs?
GI upset
Sexual dysfunction
Anxiety, nervousness
Insomnia
Fatigue, sedation
Dizziness
Are SSRIs toxic in overdose?
Nah not really
Very little risk of cardiotoxicity in overdose - which makes them good for those who are at high risk of comitting suicide
What condition may patients experience when they
a) begin on SSRIs
b) suddenly stop SSRIs
c) Which SSRI is best for avoiding these?
a) Activation syndrome
Rapid increase in serotonin can cause Nausea, anxiety, panic & agitation
Can last 2-10 days and should be discussed with patient
b) Discontinuation syndrome
Agitation, nausea, disequilibrium, dysphoria
c) Fluoxetine because longer half life
