Antidepressants Flashcards
How long does it take for symptoms to improve when an antidepressant is diagnosed? What should be done if symptoms do not improve?
Delay of 3-6 weeks after a therapeutic dose is reached before symptoms improve.
If no improvement is seen after prescription of an adequate dose for at least two months then the treatment should be switched to another agent or augmented with one
What are the classes of antidepressant?
Tricyclics (TCAs)
Monoamine Oxidase Inhibitors (MAOIs)
Selective Serotonin Reuptake Inhibitors (SSRIs)
Serotonin/Noradrenaline Reuptake Inhibitors (SNRIs)
Novel antidepressants
What is the mechanism behind tertiary TCAs?
Act on serotonin receptors
What are the side effects of tertiary TCAs?
Antihistaminic
Anticholinergic
Antiadrenergic
QT lengthening
What are some examples of tertiary TCAs?
Amitriptyline
Clomipramine
Imipramine
Doxepin
When should tertiary TCAs be avoided and why?
In high risk suicide patients as they can be taken in overdose
What is the mechanism behind secondary TCAs?
Block noradrenaline
What are the side effects of secondary TCAs?
Similar to tertiary TCAs but less severe
What are some examples of secondary TCAs?
Desipramine
Nortriptyline
What is the mechanism behind monoamine oxidase inhibtors?
Binds irreversibly to monoamine oxidase, preventing inactivation of amines (norepinephrine, dopamine, serotonin) and so increases synaptic levels
What are the side effects of monoamine oxidase inhibitors?
Antiadrenergic side effects
Antihistaminic side effects
Dry mouth
Sleep disturbance
Hypertensive crisis if eating tyramine rich foods (cheese, red wine, processed meats, beans)
Serotonin syndrome
What are some examples of monoamine oxidase inhibitors?
Phenelzine
Tranylcypromine
Selegiline
In what situation is a monoamine oxidase inhibitor most effective?
Treatment resistant depression
What mechanism is behind selective serotonin reuptake inhibitors?
Blocks presynaptic serotonin uptake
What are the side effects of selective serotonin reuptake inhibitors?
GI upset (most often nausea)
Sexual dysfunction
Anxiety
Restlessness
Nervousness
Insomnia
Fatigue/sedation
Dizziness
What are some examples of selective serotonin reuptake inhibitors?
Paroxetine
Sertraline
Fluoxetine
Citalopram
Escitalopram
Fluvoxamine
What are the symptoms of SSRI discontinuation syndrome?
Agitation
Nausea
Disequilibrium
Dysphoria
Usually lasts 7-10 days
What is the mechanism behind serotonin/norepinephrine reuptake inhibitors (SNRIs)?
Inhibits both serotonin and noradrenergic reuptake like TCAs
What are some examples of SNRIs?
Venlafaxine
Duloxetine
What are the possible uses of SNRIs?
Depression
Anxiety
Neuropathic pain
What is the mechanism behind mirtazapine?
Different mechanism of action may provide good augmentation for SSRIs
Can be used as hypnotic at lower doses
What are the side effects of mirtazapine?
Increases serum cholesterol
Sedative at low doses
Weight gain
What are the side effects of buproprion?
Seizure risk at high doses
Anxiety
Agitation
Insomnia
Psychotic side effects at high doses
What are the contraindications of buproprion?
Traumatic brain injury
Bulimia
Anorexia
What are the symptoms of serotonin syndrome?
Abdominal pain
Diarrhoea
Sweats
Tachycardia
Hypertension
Myoclonus
Irritability
Delirium
What are the potential complications of serotonin syndrome?
Hyperpyrexia
Cardiovascular shock
Death
How is serotonin syndrome prevented?
Wait for two weeks when switching from an SSRI to an MAOI, with the exception of fluoxetine where you need to wait for five weeks due to the long half-life
What is activation syndrome and when does it occur?
Activation syndrome occurs when serotonin increases in the brain and can cause nausea and increased levels of anxiety.
Usually goes away after a few days of prescription but can be prolonged.
How is antidepressant prophylaxis given?
Following first episode- 6 months prophylaxis
Following second episode- 2 years prophylaxis
Following third episode- lifelong prophylaxis
How is treatment resistant depression managed?
Generally- change SSRI to SNRI then add to SNRI
Combination of antidepressants
Adjunctive treatment with lithium
Adjunctive treatment with atypical antipsychotic (Quetipaine, olanzapine, aripiprazole)
Electroconvulsive therapy
