Tuesday, 9 November 2010

MRCP revision battle 44.2: SSRIs

Selective Serotonin Reuptake Inhibitors (SSRIs) do exactly what their name implies: selectively inhibit serotonin reuptake.

Examples include citalopram, escitalopram, fluoxetine, paroxetine and sertraline.

They are widely used for depression, anxiety, post-traumatic stress disorder and panic disorder.
Fluoxetine, paroxetine and sertraline can be used in OCD.

There are many side effects, the commonest of which is GI disturbance.

Other possible side effects to be aware of include:
  • interaction with platelet function --> increase risk of GI bleed
  • hyponatraemia
  • urinary retention

Given the increased risk of bleeding SSRIs should be avoided if on heparin/warfarin - use mirtazepine instead.

The safest SSRI post MI is sertraline.

If combined with MAOIs/moclobemide there is a serious risk of toxicity and serotonin syndrome - do not start MAOIs until 5 weeks after stopping fluoxetine, 2 weeks after stopping sertraline or 1 week after stopping any other SSRI.  Conversely you must wait 2 weeks after stopping MAOIs before starting an SSRI.

Triptans and SSRIs must also not be combined due to increased risk of serotonin syndrome.

When SSRIs are stopped they should be reduced over 4 weeks to decrease withdraw.  Paroxetine is worst on stopping.

Now on to the next battle to explore serotonin syndrome....