pharmacology depression Flashcards
What do you need for diagnosis of depression? What screening tool is used?
Patient health questionnaire 9 (PHQ-9).
Need to show anhedonia & feeling depressed & 3 of following 7. if for period of 2 weeks can be diagnosed with depression soley by using this screening tool
What is therapeutic objective for depression?
Make mood less depressed, work on self-esteem
What are some commonly prescribed SSRIs?
Sertraline, citalopram, fluoxetine
What can citalopram do and what can it interact with?
QT-prolongation. Erythromycin can also cause QT prolongation, avoid use of 2 or more drugs prolonging QT
What predisposes to QT-prolongation?
Increasing age, female, cardiac disease & metabolic disturbances (hypokalaemia)
What can fluoxetine cause potentially?
cardiac problems
What dose for each SSRI? Why not a higher dose?
Fluoxetine 20mg, citalopram & sertraline 50mg. Higher dose increases side effects & reduces effects (plateau) because serotonin levels cant increase any more (saturated)
If changing depression drugs what should you do and why?
Slowly taper dose of first drug before stopping it and wait period before starting new drug because can get rebound effect or serotonin syndrome (too much around)
What can venlafaxine contribute to and why?
Hypertension because noradrenaline mediates SNS effects on heart worsening hypertension
How can mirtazapine help? Where does it have effects?
Can help with sedation by binding on histamine receptors which contribute to sedation. Anti-emetic effects by 5HT3 receptor
What are the mechanisms of SSRI drugs?
Inhibition of serotonin reuptake resulting in accumulation of serotonin in synapse.
What is role of serotonin?
Regulation of mood, personality, wakefulness
What are targets of SSRI drugs?
Serotonin transporter
What are side effects of SSRI drugs?
GI effects (nausea, diarrhoea), sexual dysfunction, anxiety, insomnia
Where else does sertraline have effects?
Mild inhibition of dopamine transporter
Where else does citalopram have effects?
Mild antagonism of muscarinic and histamine H1 receptors
Where else does fluoxetine have effects? What should you be careful giving it with?
Mild antagonism of 5HT2A & 5GT2C receptors. Complete inhibition of CYP2D6 and significant inhibition of CYP2C19 (caution with warfarin)
What does sertraline inhibit at high doses?
Partial inhibition of CYP2D6 at high doses 150mg
What is citalopram metabolised by? What should be done on discontinuation?
Citalopram metabolised by CYP2C19. gradually decrease dose on discontinuation
What is mechanism of venlafaxine?
More potent inhibition of serotonin reuptake than norepinephrine reuptake. Noradrenaline implicated in regulation of emotions and cognition
What is target of venlafaxine?
Serotonin transporter, noradrenaline transporter
What are side effects of venlafaxine?
GI effects (nausea, diarrhoea), sexual dysfunction, anxiety, insomnia, hypertension (at high doses due to noradrenaline )
What should be done on discontinuation of venlafaxine?
Gradually decrease on discontinuation
What is mechanism of mirtazapine?
Antagonises central pre-synaptic alpha-2-adrenergic receptors, causing increased release of serotonin and norepinephrine. Antagonises 5HT2 receptor leaving 5HT1 receptor unopposed causing anti-depressant effects
What is target of mirtazapine?
Alpha-2 adrenergic receptor, 5HT2 receptor
What are side effects of mirtazapine?
Weight gain, sedation, low probability of sexual dysfunction, may exacerbate REM sleep behaviour disorder
