SNRIs

• Examples:

  • Venlafaxine
  • Duloxetine
• MOA:

  • Block the reuptake of serotonin and noradrenaline by the presynaptic membrane
  • Results in more serotonin in the synapses throughout the CNS
• Indications:

  • Treatment of major depressive disorders - usually 2nd line
  • Generalised anxiety disorder - usually 2nd line
  • Panic disorder - usually 2nd line
  • Duloxetine is also used to treat neuropathic pain - particularly diabetic neuropathy
• Venlafaxine contraindications:

  • Uncontrolled hypertension
  • Caution:
  • Cardiac arrhythmias
  • History of epilepsy (lowers seizure threshold)
  • History or family history of mania
  • At risk of angle-closure glaucoma
• Venlafaxine interactions:

  • NSAIDs (bleeding risk)
  • Anticoagulants (bleeding risk)
  • Antiplatelets (bleeding risk)
  • SSRIs (bleeding risk)
  • MAOIs - increased risk of CNS toxicity
• Venlafaxine has a similar side effect profile to SSRIs

  More likely to get withdrawal symptoms with venlafaxine - dose should be reduced over several weeks
• Venlafaxine has a higher risk than SSRIs of toxicity and death in event of overdose - caution in patients at high risk of overdose
• Venlafaxine is not high risk for weight gain