Psychopharmacology Flashcards
What are the common adrenergic/noradrenergic side effects?
- Sweat
- Tremor
- Headaches
- Nausea
- Dizziness
What are the common muscarinic side effects?
- Dry mouth, difficulty swallowing
- Difficulty urinating and possibly retention
- Hot and flushed skin
- Dry skin
What are the common histamine side effects?
- Dry mouth
- Drowsiness
- Dizziness
- Nausea and vomiting
What do antidepressants do?
Modulate serotonin activity, aiming to increase activity at post-synaptic receptors
How quickly do antidepressants work?
2-3 weeks.
WARNING increase of suicidality within this time.
What is the most common class of antidepressants, what are some alternatives?
SSRIs.
- SNRIs
- Mirtazapine
- Tricyclics
- MAOIs
How do SSRIs work?
- Reduce pre-synaptic reuptake of serotonin after release
- Which increases serotonin activity to the post-synaptic nerve
- More serotonin sits in the nerve junction
- Leads to a down regulation of post-synaptic receptors
What are the common side effects of SSRIs?
On initiation:
- Sense of restlessness, agitation on initiation
- Nausea, GI upset
- Headache
Long term:
- Weight changes
- Sexual dysfunction
- Bleeding
- Suicidal ideation
How can you get around issues of restlessness and agitation on SSRIs?
Benzodiazepines.
What is the link between antidepressants and suicide?
Regardless of the drug, there is a statistical increase in suicides around 2-3 weeks of treatment.
This is because within this time motivation and energy increases, but improvements in hope/optimism come noticeably later, causing increased suicidal ideation.
Get around this by arranging for a meeting at 2 weeks, check in on how they’re doing.
Who is especially at risk of suicide when going on antidepressants
Young men.
What are the common SSRIs?
Sertraline (50 to 200mgs)
Citalopram (20 to 40mgs)
Fluoxetine (20 to 60mgs)
Paroxetine (20 to 60mgs)
What is the ideal starting dose for Sertraline?
In the BNF, 50mgs. In reality you don’t really start anyone at a dosage below 100mgs.
What is a benefit to sertraline over other SSRIs?
Safest in cardiac disease.
What is it important to look out for with Citalopram and Escitalopram?
Watch out for QTc prolongation.
What is it important to look out for with Fluoxetine?
Serotonin syndrome.
What is it important to look out for with Paroxetine?
Discontinuation syndrome.
How do SNRIs work?
- Same as SSRIs but also bind to noradrenaline reuptake receptors also.
- Highly effective for neuropathic pain
What are the main side effects of SNRIs?
Similar to SSRIs, BUT with more issues around sedation, nausea and sexual dysfunction (both in terms of arousal and achieving orgasm).
What are some examples of SNRIs used in the UK?
Duloxetine (60 to 120mgs)
Venlafaxine (75 to 375mgs)
How does Mirtazapine work?
- Unique class
- Acts as a 5HT-2 and 5HT-3 antagonist
- Works on both Noradrenaline and Serotonin
- Strong histaminic activity even at low doses
What are the major side effects of Mirtazapine?
- Sedation
- Weight gain
Annoyingly these are sort of not dosage dependent, reducing a patient’s dose will not actually help them.
When are TCAs used?
Pretty much only when someone doesn’t like SSRIs nowadays.
What are the main side effects of TCAs?
Muscarinic and Histaminic side effects
Can be fatal in OD due to QTc prolongation and arrhythmias
Quite strong sedation, can be beneficial in insomnia.
How do MAOIs work?
- Monoamine oxidase inhibitors.
- MAOI As work on serotonin, MAOIs B work on dopamine
- All work on adrenaline
- Possibly most effective for atypical depression
What is the main issue with MAOIs
Severe interactions with other drugs.
One of the things it reacts with is Tyramine which is common in food and therefore restricts diet e.g. cheese, pickled meats, red wine.
Also, if changing someone from a MAOI to something else, need a 6 week washout.
What is Vortioxetine?
- New antidepressants
- All sorts of serotonergic activity
- Effective
- Well tolerated (most common side effect is nausea- less severe than Venlafaxine)
- Effective for patients with difficult to treat cognitive symptoms (e.g. concentration and memory, which many people notice drops along with mood but might not return)
How do you choose which antidepressant is appropriate?
- What have they used before
- Was it effective, was it tolerated
Are there any particular symptoms or comorbidities that should be considered/addressed as part of your prescription:
- Insomnia
- Weight loss
- Neuropathic pain
What antidepressant is most effective if patients have lost weight and are struggling to sleep due to their depression?
Mertazapine, causes sedation and weight gain
What antidepressant is most appropriate if patient has neuropathic pain issues?
Velafaxine or Duloxetine