Antidepressants and Anxiolytics Flashcards
What is the underlying mechanism of action for SSRI’s?
Selectively inhibit reuptake of 5-HT (serotonin) from synaptic cleft
What are the side-effects of SSRI’s?
GI- Nausea, vomiting, dyspepsia (indigestion)
CNS- Dizziness, agitation, insomnia, headache
Spinal- sexual dysfunction
Misc- Dry mouth, bleeding disorders, weight loss, hyponatremia (low sodium) in elderly
Can cause transient increase in suicidal ideation especially in <25yrs
What are the side-effects of discontinuing SSRI’s?
Mood change
Dizziness
Nausea
Diarrhoea
Headache
What are the 3 main SSRI types?
Citalopram
Fluoxetine
Sertraline
Which SSRI can affect an ECG reading and how?
Citalopram
Dose dependent QT prolongation (Long-QT → Torsades des Pointes)
Which SSRI is typically used first line for anxiety disorders?
Sertraline
Good cardiac safety profile(e.g. post-MI), commonly used first for anxiety disorders
Which SSRI has the longest half-life and is also the only one licensed for under 18’s?
Fluoxetine
If on Warfarin, NICE recommends using mirtazapine instead of SSRI’s. True/false?
True
What is the underlying mechanism of action for SNRI?
Blocks SERT (serotonin transporter) and NET (norepinephrine transporter).
Side effects of SNRI’s?
Same side effects as SSRIs + hypertension, tachycardia, QTc prolongation
Examples of SNRI’s?
Venlafaxine
Duloxetine
Apart from anxiety and depression related, what other things can the SNRI duloxetine be used for?
Also good also for neuropathic pain and stress incontinence
What depressive symptoms is venlafaxine good for treating?
Anhedonia /anergia symptoms
Anergia = abnormal lack of energy
Anhedonia = abnormal loss of ability to feel pleasure when usually pleasure is felt.
What is the underlying mechanism of action for mirtazapine?
NaSSA (antagonises a2-adrenergic + selective serotonin receptors, also histamine)
What are symptomatic features of mirtazapine that enable it to combat SSRI side-effects?
Increased sleep and increased appetite, to be taken at night.
Why is mirtazapine commonly given alongside SSRI’s?
Mirtazapine promotes increased sleep and increased appetite.
This helps reduce the side-effects of SSRI’s (i.e. indigestion, vomiting and insomnia).
Trazodone has an SSRI kind of action. True/false?
False
SNRI kind of action
Why is trazodone used more commonly in the elderly?
Used more in elderly due to sedative properties and minimal anticholinergic side-effects.
What drug can also be used in frontotemporal dementia?
Trazodone
What hormones do tricyclic antidepressants act on?
Serotonin and noradrenaline (similar mechanism to SNRI’s)
What are the side effects of tricyclic antidepressants?
Anticholinergic (Drowsiness, dry mouth, blurred vision, constipation, urinary retention)
QT prolongation
Orthostatic Hypotension
Cardiotoxic in overdose
Why are tricyclines commonly used in 3rd/4th line treatment?
Due to toxicity in overdose plus side effects
Examples of tricyclic antidepressants (usually ends in -ine)?
Imipramine
Amitriptyline
Clomipramine
Which tricyclic antidepressant functions well in OCD management?
Clomipramine
What is the “cheese reaction” in monoamine oxidase inhibitors?
What are some other foods that should be stopped with this med?
Hypertensive crisis caused by inhibition of MAO-A in GI tract, stops breakdown of dietary tyramine
Foods containing tyramine include cheese, smoked meats, red wine, beer
Examples of reversible and irreversible MAO-A inhibitors?
Irreversible- e.g. Phenelzine,
Reversible- e.g. Moclobemide (has less strict dietary requirements)
What is GABA (Gamma-aminobutyric acid)?
GABA is a neurotransmitter, which means it’s a chemical messenger in the brain.
It’s one of the main inhibitory neurotransmitters, meaning it helps to calm down or inhibit the activity of nerve cells in the brain.
What do benzodiazepines do to the neurotransmitter GABA in the brain?
Benzodiazepines enhance the activity of GABA in the brain, leading to calming and relaxing effects.
GABA itself is a neurotransmitter that helps to inhibit the activity of nerve cells, promoting feelings of relaxation and reducing anxiety.
How do benzodiazepines reduce the neuronal firing?
By increasing the Cl- that enter the neurons.
What are the main problems associated with benzodiazepines?
Patients can develop tolerance and are addictive
Avoid in pregnancy - risk of foetal malformation, “floppy baby syndrome”
Associated lethargy with breastfeeding
Increases falls risk, can worsen delirium
Withdrawal syndrome similar to alcohol withdrawal (similar mechanism)
What are benzodiazepines used first line in?
Catatonia (abnormality of movement due to disturbed mental state-typically schizophrenia).
Status Epilepticus (e.g. buccal midazolam)
What is the difference between reversible and irreversible MAO-A inhibitors?
Reversible: Bind to the MAO-A enzyme temporarily and can be displaced by other molecules.
They inhibit the activity of MAO-A while they are bound to the enzyme but do not permanently alter the enzyme’s structure.
Irreversible: Bind irreversibly to the MAO-A enzyme, forming a covalent bond that permanently alters the enzyme’s structure.
Once bound, irreversible MAO-A inhibitors permanently inhibit the activity of the enzyme.
