Pharmacological Treatment of Affective and Anxiety Disorders Flashcards
Antidepressants - mechanism
- Not fully known
- To do with the neurotransmitters serotonin and noradrenaline
- Increase levels of these in brain
- This changes receptors in the brain
Antidepressants - indications
- Unipolar and bipolar depression
- Organic mood disorders
- Schizoaffective disorder
- Anxiety disorders
- Including OCD, panic, social phobia, PTSD
Antidepressants - general guidelines
- Antidepressant efficacy is similar, so selection based on past history of response, side effect profile and coexisting medical conditions
- Delay of 2-4 weeks after therapeutic dose is achieved before symptoms improve
- If no symptoms seen after at least 2 months and adequate dose, switch to another antidepressant or augment with another agent
What is selection of antidepressant based on?
- Antidepressant efficacy is similar, so selection based on past history of response, side effect profile and coexisting medical conditions
How long do antidepressants take to work?
- Delay of 2-4 weeks after therapeutic dose is achieved before symptoms improve
- If no symptoms seen after at least 2 months and adequate dose, switch to another antidepressant or augment with another agent
What are the different classess of antidepressants?
Classification:
- Tricyclics (TCAs)
- Monoamine oxidase inhibitors (MAOIs)
- Selective serotonin reuptake inhibitors (SSRIs)
- Serotonin/noradrenaline reuptake inhibitors (SNRIs)
- Novel antidepressants
What does the following stand for:
- TCAs
- MAOIs
- SSRIs
- SNRIs
What are the 2 types of TCAs?
- Tertiary TCAs
- Have tertiary amine side chains
- These are prone to cross react with other types of receptors leading to side effects
- Drugs – Imipramine, Amitriptyline, Doxepin, Clomipramine
- Secondary TCAs
- Often metabolites of tertiary amines
- Primarily blocks noradrenaline
- Drugs – Desipramine, Notritriptyline
Mechanism of:
- tertiary TCAs
- secondary TCAs
- Tertiary TCAs
- Have tertiary amine side chains
- These are prone to cross react with other types of receptors leading to side effects
- Drugs – Imipramine, Amitriptyline, Doxepin, Clomipramine
- Secondary TCAs
- Often metabolites of tertiary amines
- Primarily blocks noradrenaline
- Drugs – Desipramine, Notritriptyline
Drugs of:
- tertiary TCAs
- secondary TCAs
- Tertiary TCAs
- Have tertiary amine side chains
- These are prone to cross react with other types of receptors leading to side effects
- Drugs – Imipramine, Amitriptyline, Doxepin, Clomipramine
- Secondary TCAs
- Often metabolites of tertiary amines
- Primarily blocks noradrenaline
- Drugs – Desipramine, Notritriptyline
Effect - TCAs
- Increases both serotonin, dopamine and noradrenaline
Side effects - TCAs
- Potentially unacceptable side effect profile
- Antihistaminic
- Anticholinergic
- Lethal in overdose
- Can cause QT lengthening
Mechanism - MAOIs
- Bind irreversible to monoamine oxidase, preventing inactivation of amines such as norepinephrine, dopamine and serotonin leading to increased synaptic levels
Indications - MAOIs
- Resistant depression
Side effects - MAOIs
- Orthostatic hypertension
- Weight gain
- Dry mouth
- Sedation
- Sexual dysfunction
- Sleep disturbance
Drug interactions - MAOIs
- Tryamine-rich foods or sympathomimetics
- Causes “cheese reaction”, which is a hypertensive crises
- Foods include cheese and red wine
- If taken with meds that increase serotonin or have sympathomimetic actions
- Serotonin syndrome
- Side effects – abdominal pain, diarrhoea, sweats, tachycardia, HTN, myoclonus, irritability, delirum. Maybe even hyperpyrexia, cardiovascular shock and death
What is the most commonly used class of antidepressants?
SSRIs
Drugs - SSRIs
- Sertraline
- Fluoxetine (Prozac)
Mechanism - SSRIs
- Block the presynaptic serotonin reuptake
Indications - SSRIs
- Anxiety
- Depression
Side effects - SSRIs
- GI upset
- Sexual dysfunction (30+%)
- Anxiety
- Restlessness
- Nervousness
- Insomnia
- Fatigue or sedation
- Dizziness
- Very little risk of cardiotoxicity in OD
- Can develop a discontinuation syndrome with agitation, nausea, disequilibrium and dysphoria if stopped quickly
- Activation syndrome
- Caused by increase in serotonin
- Symptoms – nausea, increased anxiety, panic and agitation
- Typically lasts 2-10 days
What is activation syndrome caused by?
- Caused by increase in serotonin
What are symptoms of activation syndrome?
- Symptoms – nausea, increased anxiety, panic and agitation
- Typically lasts 2-10 days
Drugs - SNRIs
- Venlafaxine
- Duloxetine
Mechanism - SNRIs
- Inhibit serotonin and noradrenergic reuptake like the TCAs
- But without the antihistamine, antiadrenergic or anticholinergic side effects
Indications - SNRIs
- Depression
- Anxiety
- Possibly neuropathic pain