Psychopharmacology - Part 1 Flashcards
What is the general guidelines for antidepressant use?
Efficacy is similar
Selection on side effect profile and coexisting medical conditions
Delay of 2-4 weeks
Switch after 2 months if no improvement seen
What are the indications for antidepressants?
Unipolar and bipolar depression, organic mood disorders, schizoaffective disorder, anxiety disorders including OCD, panic, social phobia and PTSD
What are the classifications of antidepressants?
SSRIs
Tricyclics TCAs
Monoamine oxidase inhibitors MAOIs
SNRIs
Novel antidepressants
Describe SSRIs
Block presynaptic serotonin reuptake
Treat both anxiety and depression
Very little risk to cardiotoxicity in overdose
What are the side effects of SSRIs?
GI upset, sexual dysfunction, anxiety, restlessness, nervousness, insomnia, fatigue and dizziness
What is discontinuous syndrome?
On SSRIs
Agitation, nausea, disequilibrium and dysphoria
What is activation syndrome?
On SSRIs
Increased serotonin
Nausea, anxiety, panic and agitation
Typically 2-10 days
Can be distressing for the patient
What are the pros of fluoxetine?
Long half life so decreased incidence of discontinuation syndrome
Initially activating so may provide increased energy
Can give one tablet to taper someone off SSRIs
What are the cons of fluoxetine?
Long half life and active metabolite may build up
Significant P450 interactions so not good if on a number of meds
More likely to induce mania
Initial activation syndrome
What are the pros of sertraline?
Very weak P450 interactions
Short half life with lower build up of metabolites
Less sedating
What are the cons of sertraline?
Max. absorption requires full stomach
Increased number of GI side effects
Describe TCAs
Very effective but potentially unacceptable side effect profile - antihistamine, anticholinergic and antiadrenergic
Lethal in overdose
Can cause QT lengthening
Describe tertiary TCAs
Amine side chains
Prone to cross with other types of receptors which leads to more side effects
Have active metabolites including desipramine and nortiptyline
Describe secondary TCAs
Often metabolites of tertiary amines
Primarily block noradrenaline
Side effects are the same as tertiary but less severe
Desipramine and nortriptyline
Describe MAOIs
Bind irreversibly to monoamine oxidase so prevent inactivation of amines leading to increased synaptic levels
Effective against resistant depression
What are the side effects of MAOIs?
Orthostatic hypertension, weight gain, dry mouth, sedation, sexual dysfunction and sleep disturbance
What is the Cheese reaction?
Hypertensive crisis can develop when on MAOIs are taken with tyramine rich foods or sympathomimetics
What is serotonin syndrome?
If take MAOIs with meds that increase serotonin or have sympathomimetic actions
Abdominal pain, diarrhoea, sweats, tachycardia, HTN, myoclonus, and delirium
Can lead to hyperpyrexia, cardiovascular shock and death
Wait 2 weeks from switching from SSRIs to MAOI
Describe SNRIs
Inhibit both serotonin and NA reuptake but without antihistamine, antiadrenergic and anticholinergic side effects
Used for depression, anxiety and possible neuropathic pain
What are the pros of venlafaxine?
Minimal drug interactions
Short half life and fast renal clearance avoids build up
What are the cons of venlafaxine?
Can cause a 10-15mmHG dose dependant increase in diastolic BP
Significant nausea
Bad discontinuation syndrome and taper recommended
Sexual side effects
What are the pros of duloxetine?
Some efficacy in physical symptoms of depression
Less BP increase
What are the cons of duloxetine?
CYP2D^ and CYP1A2 inhibitor
Not stable within the stomach
High drop out rate
Describe vortioxetine
SNRI
Less GI side effects and changes in BP
Expensive
Specialists only
What are the pros of mirtazapine - novel antidepressant?
Different mechanism of action may provide good augmentation strategy to SSRIs
Can be utilised as a hypnotic
What are the cons of Mirtazapine?
Increases serum cholesterol by 20%
Very sedating at lower doses
Can become activating and require change
Associated with weight gain
What is the treatment for treatment resistant depressant?
Combination of antidepressants - SSRI or SNRI with mirtazepine
Adjunctive treatment with lithium
Adjunctive treatment with atypical antipsychotic
ECT
How do you treat treatment resistant anxiety?
High dose SSRI first
Combination of antidepressants - SSRI or SNRI with mirtazepine
Adjunctive treatment with atypical antipsychotics
Adjunctive treatment with pregabalin or buspirone
Avoid diazepam
Describe prophylaxis in depression
First episode continue for 6 months to a year
Second - continue for 2 years
Third - life long
