Psychopharmacology 1 Flashcards
List the indications for prescribing antidepressants
Unipolar/bipolar depression, organic mood disorders, schizoaffective disorder, anxiety disorders including OCD, panic, social phobia and PTSD
How long does it typically take for antidepressants to start improving symptoms?
3-6 weeks
Name the classifications of antidepressant medications
- Tricyclics
- Monoamine Oxidase Inhibitors (MAOIs)
- Selective Serotonin Reuptake Inhibitors (SSRIs)
- Serotonin/Noradrenaline Reuptake Inhibitors (SNRIs)
What are the drawbacks of TCAs?
- Potentially unacceptable side effect profile
- Lethal in overdose
- Can cause QT lengthening
Describe the mechanism of tertiary TCAs
- They have amine side chains with can react with a variety of receptors
- Acts predominantly on serotonin receptors
List the possible side effects of TCAs
- Anti-histaminic: sedation and weight gain
- Anti-cholinergic: dry mouth, dry eyes, constipation, memory deficits and delirium
- Anti-adrenergic: orthostatic hypotension, sedation and sexual function
Give four examples of tertiary TCAs
Imipramine, amitryptyline, doxepin and chlomipramine
Describe the features of secondary TCAs
- Often metabolites of tertiary amines
- Primarily block noradrenaline
- Side effects are the same as tertiary TCAs but generally less severe
Give two examples of secondary TCAs
Desipramine and nortriptyline
Describe the mechanism of monoamine oxidase inhibitors
They bind irreversibly to monoamine oxidase thereby preventing inactivation of amines (noradrenaline, dopamine and serotonin etc.) to increase synaptic levels
List the possible side effects of monoamine oxidase inhibitors
Orthostatic hypotension, weight gain, dry mouth, sedation, sexual dysfunction and sleep disturbance
What is the potential dangerous consequence of monoamine oxidase inhibitors and what causes it?
Hypertensive crisis - caused by taking MAOIs with tyramine rich foods (cheese, wine etc.)
Name the cause of serotonin syndrome and how it presents
- MAOIs being taken alongside meds that increase serotonin or have sympathomimetic actions
- Abdominal pain, diarrhoea, sweats, tachycardia, HTN, myoclonus, irritability and delirium
- Can lead to hyperpyrexia, CVS shock and death
Describe the mechanism of selective serotonin reuptake inhibitors and the indications for use
- Block the presynaptic serotonin reuptake
- Anxiety and depression
List the most common side effects of SSRIs
GI upset, sexual dysfunction, anxiety, restlessness, nervousness, insomnia, fatigue/sedation and dizziness
What can happen if an SSRI is stopped suddenly?
-Discontinuation syndrome: agitation, nausea, disequilibrium and dysphoria
What are the pros and cons of Paroxetine?
- Pros: short half life and sedation properties (good for anxiety and insomnia)
- Cons: significant CYP2D6 inhibition, sedation, weight gain, anticholinergic effects and likely to cause discontinuation syndrome
What are the pros and cons of sertraline?
- Pros: weak P450 interactions, short half life and less sedating compared to paroxetine
- Cons: max absorption requires a full stomach and there is an increased number of GI adverse drug reactions
What are the pros and cons of fluoxetine (prozac)?
Pros
- Long half life (decreased incidence of discontinuation syndrome)
- Initially activating so may provide increased energy
Cons
- Long half life may cause active metabolite to build up
- Significant P450 interactions (not a good choice in patients on multiple meds)
- Initial activation may increase anxiety and insomnia
- More likely to induce mania than other SSRIs
What are the pros and cons of citalopram?
Pros
- Low inhibition of P450 enzymes so fewer drug interactions
- Intermediate half life
Cons
- Dose dependant QT interval prolongation (>40 mg not recommended)
- Can be sedating
- GI side effects
What are the pros and cones of escitalopram?
Pros
- Low overall inhibition of P450 enzymes
- Intermediate half life
- More effective than citalopram in acute response and remission
Cons
- Does dependent QT interval prolongation with doses of 10-30mg daily
- Nausea, headaches
What are the pros and cons of fluvoxamine?
Pros
- Shortest half life
- Found to possess some analgesic properties
Cons
- Shortest half life
- GI distress, headaches, sedation and weakness
- Strong inhibitor of CYP1A2 and CYP2C19
What are the benefits of serotonin/noradrenaline reuptake inhibitors?
-Inhibit both serotonin and noradrenergic reuptake but without the antihistamine, antiadrenergic or anticholinergic side effects that TCAs have
What are the indications for SNRIs?
Depression, anxiety and neuropathic pain
Give the common examples of SNRIs
Venlafaxine, duloxetine
What are the pros and cons of venlafaxine?
Pros
- Minimal drug interactions and P450 activity
- Short half life and fast renal clearance
Cons
- Can cause an increase in diastolic BP
- May cause significant nausea
- Can cause a bad discontinuation syndrome (taper recommended)
- QT prolongation
- Sexual side effects in >30%
What are the pros and cons of duloxetine?
Pros
- Data may suggest efficacy for the physical symptoms of depression
- Less BP increase compared to venlafaxine
Cons
- CYP2D6 and CYP1A2
- Cannot break capsule - active ingredient is not stable within the stomach
- Higher drop out rate (in pooled analysis)
What are the pros and cons of mirtazapine?
Pros
- Different mechanism of action may provide good augmentation strategy to SSRIs
- Can be utilised as a hypnotic at lower doses
Cons
- Increases serum cholesterol and triglycerides in some patients
- Very sedating at lower doses
- Associated with weight gain
What are the pros and cons of buproprion?
Pros
- Good for use as an augmenting agent
- No weight gain, sexual side effects etc.
- Low induction of mania
- Second line ADHD agent
Cons
- May increase seizure risk
- Should be avoided in patients with traumatic brain injury, bulimia and anorexia
- Does not treat anxiety
- Has abuse potential
What are the management options for treatment resistant depression?
- Combination of antidepressants e.g. SSRI or SNRI with Mirtazepine
- Adjunctive treatment with lithium
- Adjunctive treatment with an atypical antipsychotic e,g, quetapaine, olanzapine or aripiprazole
- ECT
Name the commonly used SSRIs
Paroxetine, sertraline, fluoxetine, citalopram, escitalopram, fluvoxamine
What are the indications for mood stabilisers?
Bipolar disorder, cyclothymia and schizoaffective