Antidepressants Flashcards
What are the 2 types of depression? Differentiate between them
- Unipolar - mood swings always in the same direction (ie. repeated episodes of feeling emotionally low)
- Bipolar - alternating depression and MANIA
Describe the monoamine theory
Deficits in monoamine neurotransmitters (noradrenaline and 5-HT) causes depression.
List the classes of antidepressants
- Monoanime oxidase inhibitors (MAOIs)
- Tricyclic antidepressants
- **Selective serotonin reuptake inhibitors (SSRIs)
- Selective noradrenaline uptake inhibitors
- 5-HT and noradrenaline uptake inhibitors
What is the MOA of MAOIs?
Monoanime oxidase breaks down monoanimes.
Inhibit it = more monoanime neurotransmitters
MAO-A are serotonin selective
MAO-B is dopamine/noradrenaline selective
Name the MAO-B selective inhibitor used in Parkinson’s
Selegiline
When is selegiline used?
MAO-B selective inhibitor used in Parkinson’s
Name a non-selective MAOI and its unique property
Phenelzine
It is an irreversible inhibitor.
What are the adverse effects of MAOIs?
- Postural hypotension - sympathetic block due to accumulation of dopamine
- Restlessness and insomnia
- Cannot be combined with other drugs that agonise serotonin receptors - can cause hyperexcitability
What is the MOA of tricyclic antidepressants?
Monoamine (serotonin and noradrenaline) reuptake inhibitor
Name at least 2 non-selective tricyclic antidepressants
Imipramine
Amitriptyline
Nortriptyline
Name a tricyclic antidepressant selective for noradrenaline/dopamine
Desipramine
Of the non-selective tricyclic antidepressants, which drug has milder side effects and more desirable?
Nortriptyline
Second gen TCA
List the adverse effects of TCAs
- Sedation due to histamine receptor antagonism** but can develop tolerance in 1-2 weeks
- Postural hypotension (different from MAOIs which is due to non-selective sympathetic block, TCA is due to alpha adrenoreceptor sympathetic block)
- Cholinergic symptoms (dry mouth, blurred vision and constipation due to muscarinic receptor antagonism)
What is the most commonly used class of drugs for anti depressants?
Selective serotonin reuptake inhibitors (SSRIs)
What is the most widely prescribed antidepressants?
Fluoxetine
*** List at least 2 advantages of using SSRIs
- Low affinity for alpha adrenoreceptors (TCA) -> reduce risk of cardiovascular overstimulation -> SAFER IN OVERDOSE
- Lack of effect at histamine receptors (TCA)
-> reduce sedation - Low affinity for muscarinic receptors (TCA) -> minimal cholinergic side effects
- Overall, the less side effects compared to TCA/MAOIs leads to BETTER COMPLIANCE
Compare between SSRIs and TCA
SSRIs has less side effects which leads to better compliance. Can prescribe higher dose as there is a lower risk of overdose.
Because of the adverse effects of TCA and fear of overdose, TCA is often prescribed at subtherapeutic dose.
What are the adverse effects of SSRIs?
Nausea
Insomnia
Sexual dysfunction
**SEROTONIN SYNDROME
Name 2 SSRIs
Citalopram
Fluoxetine
What is the most severe adverse effect associated with serotonin?
SEROTONIN SYNDROME
Happens when there is DDI between drugs with serotoninergic activity (eg. MAOIs, TCA)
Tremor
Hyperthermia
Cardiovascular collapse
What is the brand name of fluoxetine?
Prozac
What is drug makes up the brand Prozac?
Fluoxetine
What is the first line class of antidepressant?
SSRIs (ie. fluoxetine, citalopram)
If patient is not responsive to SSRI treatment, what is the second line class of drug to give?
Noradrenaline reuptake inhibitors like reboxetine
What is the SSRI with the highest selectivity for serotonin?
Citalopram
Name a noradrenaline reuptake inhibitor
Reboxetine
What is reboxetine?
A noradrenaline reuptake inhibitor
List the adverse effects of reboxetine
More noradrenaline = more stimulation of CNS/SNS = less PNS
- Anticholinergic effects - dry mouth, constipation
- Stimulation of CNS = insomnia
- Stimulation of SNS = tachycardia
Name a serotonin and noradrenaline reuptake inhibitors (SNRIs)
Venlafaxine
Duloxetine
Will taking SNRIs with SSRIs increase the risk of serotonin syndrome?
Yes, since they both increase activity at serotonin receptors
List some adverse effects of SNRIs
A mix of SSRI and NARI symptoms
SSRI: nausea, insomnia, sexual dysfunction, serotonin syndrome
NARI: dry mouth, constipation, tachycardia, insomnia
List some adverse effects associated with increased activity at serotonin receptors
Nausea
Insomnia
Sexual dysfunction
List some adverse effects associated with increased activity at NA receptors
Stimulation of CNS = insomnia and SNS = tachycardia
Less stimulation of PNS = dry mouth, constipation
If a patient is not responsive to SSRI treatment, what are the other class of drugs that can be prescribed?
NARIs
SRNIs
What is mirtazapine?
A noradrenaline and specific serotonin antidepressant
What is bupropion?
A norepinephrine and DOPAMINE reuptake inhibitor
What is agomelatine?
Agonist of melatonin MT1 and MT2 receptors
What is ketamine?
A glutamate NMDA receptor antagonist
