Anti-depressants Flashcards
What are the 2 types of psychoses?
- Affective disorders
- Schizophrenia
What are the 2 types of affective disorders?
- Depression
- Mania
What are the different types of depression - the 2 main types and the 2 subtypes for one of these?
- Bipolar depression
- Unipolar depression - reactive and endogenous
1) What is unipolar depression and what are the 2 types and describe these 2 types, including the hereditary pattern of it?
2) Describe the onset of unipolar depression
1)
- Unidirectional mood swings
- Reactive - in response to stressful life events - non-familial pattern
- Endogenous - unrelated to external stresses - familial pattern
2)
- Late onset in adulthood
1) What is bipolar depression?
2) Describe the onset of bipolar depression?
3) What is the main treatment for bipolar depression and what does it do?
1)
- Bipolar depression - oscillating depression and mania (hyper-excitability with opposite symptoms to depression)
2)
- Strong hereditary tendency - early onset
3)
- Lithium - mood-stabilising drug
Briefly describe the monoamine theory of depression and mania
- Depression = ↓ central monoamine transmission
- Mania = ↑ central monoamine transmission
Apart from monoamine transmission, what else may be involved in the pathophysiology of the depression that is observed in depressed patients?
- HPA axis involvement potentially → ↑ CRH in depressed patients
How might depression affect memory?
- Hippocampal degeneration due to chronic depression
Name an example of a TCA?
- Amiltryptiline
Describe how TCAs work as anti-depressants, and also what receptors do they act on?
- Neuronal monoamine reuptake inhibitors (NA, 5-HT, little dopamine)
- By antagonising alpha-2 receptors, TCAs prevent inhibition of NA release that alpha-2 receptors normally have - therefore they enhance NA release
- Act on alpha-2, muscarinic AChRs, histamine receptors, 5-HT receptors
Describe the pharmacokinetics of TCAs
- V. plasma protein bound
- Hepatic metabolism generates active metabolites
- Renal conjugation via glucuronide conjugation
- Long half-life
Give 3 unwanted efffects of TCAs at therapeutic dose
- Amiltryptiline gives atropine-like effects - dry mouth, blurry vision, constipation, urinary retention
- Postural hypotension - vasomotor centre mediated central effect
- Sedation due to H1 (histamine) antagonism
Give 2 unwanted effects of TCAs at a high dose - i.e. in acute toxicity
- CNS - excitement, delirium, seizures - coma, respiratory depression
- CVS - cardiac dysrhythmias - ventricular fibrillation and sudden death
List 5 drug interactions that TCAs can have
- ↑ TCA effects with co-administration with aspirin and phenytoin - to do with plasma protein bound TCA
- Warfarin displaces TCAs from binding sites → moves plasma levels to toxic range
- Hepatic microsomal enzymes metabolise TCAs, so if co-administered with other drugs which are also metabolised by hepatic microsomal enzymes → ↑ TCAs
- TCAs potentiate CNS depressants like alcohol
- TCAs interact with anti-hypertensive drugs unpredictably
Name one structural feature of TCAs
- 3 rings