Antidepressants Flashcards
Mechanism of action of SSRIs
- Inhibits reuptake of serotonin.
- Causes an increased concentration in the synapse
- Takes several weeks to have full effect
Clinical indications for SSRIs
- Depression
- Anxiety disorders e.g. GAD, OCD & PTSD
Side effects of SSRIs
- agitation
- sexual dysfunction
- nausea
- diarrhoea
- dizziness
- headaches
- insomnia
Why do SSRIs need to dosed down slowly?
Abrupt withdrawal causes discontinuation syndrome
(dizziness, fatigue, headaches etc)
Which SSRI causes a QT prolongation?
Citalopram
What is important to tell a patient who is started on an SSRI?
Initially, their symptoms will worsen before it gets better
There is an initial increase in suicide risk in <25 year olds
Give 3 examples of SSRIs
- sertraline
- fluoxetine
- citalopram
Examples of Tricyclic antidepressants
Amitriptyline, Clomipramine, Imipramine.
Mechanism of action of TCAs
Inhibit the re-uptake of sertraline and noradrenaline.
Also act as antagonists and several other neurotransmitter receptors e.g muscarinic, alpha1 and H1.
Which TCA is licensced for OCD?
Clomipramine
Side effects of TCA
Anticholinergic – dry mouth, urinary retention etc
Drowsiness, headache
Cardiovascular – tachycardia, QT prolongation
Withdrawal effect – nausea, anxiety, sweating, insomnia.
What can happen in TCA toxicity/overdose?
cardiac arrhythmias (ventricular fibrillation)
seizures
hypotension
Give 3 examples of MAOIs (Monoamine Oxidase Inhibitors)
Phenelzine, Isocarboxazid, Moclobemide
Why are MOIs not usually used?
Rarely used now due to interactions with foods and other medications. Reserved for patients who have not responded to other treatments.
What condition does a patient who has not responded to medication have?
Refractory (depression or anxiety)
What is Mirtazapine?
It is a presynaptic alpha 2 adrenoreceptor antagonist
Indication(s) of mirtazapine
used to treat depression and sometimes obsessive compulsive disorder (OCD) and anxiety
Examples of SNRIs
Venlafaxine and Duloxetine
Indications for SNRIs
Usually second line treatment for depression. Can be used for Generalised anxiety disorder.
When are Venlafaxine and Mirtazapine used in combination?
Venlafaxine and mirtazapine in combination are increasingly used in clinical practice to treat treatment-refractory depression. (depression that has not responded to other medications)
What food cannot be consumed by someone taking MOAIs?
Cheese
As it contains tyramine
This can cause hypertensive crisis
What is the risk of SSRI therapy in third trimester of pregnancy?
There is a risk of persistent pulmonary hypertension of the newborn.
