Depression

• what are the 2 key symptoms of depression?

  persistent low or depression mood

  loss of interest or pleasure in previously enjoyable activities
• what are the different classes of antidepressants?

  TCAs, MAOI, SSRI, SNRI and atypical antidepressants
• what are the risk benefits of TCAs?

  lower seizure threshold, can cause cardiac toxicity - avoid in history of CVD, can increase ACh burden - avoid in elderly

  largely metabolised by liver so avoid in hepatic impairment

  causes sedation, weight gain, memory problems, confusion and potentially hypotension
• what are the risk/benefits for SSRIs?

  relatively good CV profile, safer in overdose and better tolerated compared to TCAs

  can have bleeding risks - blocking serotonin transporter molecules on platelet membranes which decreases platelet serotonin stores = increased risk of bleeding and increased risk of GI bleed in elderly
• what are the risk benefits of MAOIs?

  MAOIs cause muscarinic receptor antagonism which cause antimuscarinic side effects such as restlessness

  cheese reaction - interaction with tyramine rich foods such as cheese
• what are the risk benefits of atypical antidepressants?

  can cause H1 antagonism - sedation, increased appetite and weight gain

  can also cause blood disorders

  black box suicide warning

  however, a good alternative to TCAs in CVD
• what are the risk benefits of SNRIs?

  high doses of venlafaxine also inhibit DA uptake to some extent

  low dose duloxetine = dual action - works on serotonin and NA
• what are examples of SSRIs?


  fluoxetine, sertraline, citalopram, escitalopram
• what are examples or TCAs?

  amitriptyline, nortriptyline
• what are examples of MAOIs?


  irreversible = tranylcypomine

  reversible = moclobemide
• what are examples of SNRIs?

  venlafaxine, duloxetine
• what are examples of atypical antidepressants?

  mirtazipine
• what is the order of prescribing for antidepressants?

  Start with SSRIs, if still persistent switch to another SSRI, if still persistent switch to another agent from a different class

  if no response to 3 ADs, check concordance, review diagnosis and consider if social problems are maintaining depression
• what are the counselling points for SSRIs?

  be aware of possible increase in suicidal thoughts/tendencies in early stages - counsel about risk and what to do - suicide prevention lines which are 24/7 - looking out for signs of increased depression or self-harming behaviours
• what is the strategy to discontinue antidepressants?

  gradual dose reduction - over 4 weeks or 6 months if on long term maintenance treatment
• what are discontinuation symptoms?

  withdrawal - can vary in type and severity - can be problems sleeping, sweating, vertigo, palpitations and altered feelings

  NOTE: make sure to counsel patients on this possibility and that this doesn't affect everyone

  they usually occur 5 days after withdrawing treatment and are self-limiting - their depression is not getting worse

  offer regular reviews and provide written information
• describe SSRI drug interactions

  most SSRIs inhibit P450 enzymes but vary in their potency to do so - citalopram has the fewest pk interactions whereas paroxetine, fluoxetine and fluvoxamine have the most pk interactions
• describe MAOIs drug interactions

  cheese reaction - tyramine rich foods can cause hypertensive crises which can be fatal
• what is serotonin syndrome?

  rare but potentially life threatening condition caused by excessive stimulation of CNS and peripheral serotonin receptors
• what are the symptoms of serotonin syndrome?

  split into autonomic hyperactivity, neuromuscular changes and mental status changes

  examples in order include: hypertension/tachycardia, tremor/hypertonicity and agitation