Pharmacology Flashcards
What is the monoamine hypothesis?
- This states that depression results from a functional deficit of monoamine transmitters in particular serotonin (5-HT) and noradrenaline
- This was based off the evidence that drugs that deplete stores of monoamines e.g. resperine can induce low mood
- Also, CSF from depressed patients have reduced levels of monoamines or metabolites
- Most drugs that treat depression act to increase monoaminergic transmission
- But it’s not that simple, these are just parts of a complex pathway that are modifiable
List 4 SSRIs?
fluoxetine, citalopram, sertraline, paroxetine
MOA of SSRIs?
selectively inhibit reuptake of serotonin (5-HT) from the synaptic cleft
Common side effects of SSRIs?
Common side effects: nausea, headache, worsened anxiety, transient increase in self harm in adolescents and young people, sweating, vivid dreams, sexual dysfunction, hyponatraemia (important in the elderly), discontinuation effects
Which SSRIs have longest and shortest half life? What is the clinical relevance of this?
- Paroxetine has the shortest half life and produces the most pronounced withdrawal effects, it can be really difficult to get people off this, so best avoided
- Fluoxetine has the longest half life and produces the fewest withdrawal symptoms
What SSRI increases QT interval?
citalopram
Give 4 examples of tricyclic antidepressants?
imipramine, dosulepin, amitriptyline, lofepramine
MOA of tricyclic antidepressants?
block the uptake of monoamines serotonin and noradrenaline into presynaptic terminals equally
Common side effects of tricyclic antidepressants?
most are due to their anticholinergic effect as the drugs also block muscarinic receptors, these effects include blurred vision, dry mouth, constipation, urinary retention, sedation, weight gain, postural hypotension, tachycardia, arrhythmias, cardiotoxicity in overdose
Are monoamine oxidase inhibitors prescribed as antidepressants much now?
no
What is an example of a NRI?
reboxetine
What are 2 examples of dual reuptake inhibitors (SNRIs)?
venlafaxine and duloxetine
side effects of SNRIs and NRIs are similar to?
side effects of SSRIs
9 clinical uses of antidepressants?
- Moderate to severe depression
- Dysthymia
- Generalised anxiety disorder
- Panic disorder
- OCD
- PTSD
- Premenstrual dysphoric disorder
- Bulimia nervosa
- Neuropathic pain
What is serotonin syndrome caused by?
- Uncommon but can be serious
- Usually triggered when taking SSRI/ SNRI with another medication that increases serotonin e.g. St John’s Wort
Symptoms and severe symptoms of serotonin syndrome?
- Symptoms include: agitation, confusion, muscle twitching, sweating, shivering, diarrhoea
- Severe symptoms: seizures, arrhythmias and unconsciousness
SSRIs and NSAIDS combine _____
increase risk of GI bleeding so should give a PPI
What is mirtazipine?
tetracyclic antidepressant - noradrenergic and specific serotonergic antidepressant
When checking lithium levels samples should be taken ________
12 hours post dose
Rough MOA of antipsychotics ?
- Schizophrenia is thought to be partially due to the firing of aberrant dopaminergic neurons
- So, if you can block the receptors are reduce the effect of firing you will treat the symptoms (there are other factors that contribute to schizophrenia but this is just a known part of the pathway we can treat)