Antidepressant stopping & switching

All antidepressants can cause discontinuation symptoms with the possible exceptions of agomelatine and vortioxetine.

Abrupt withdrawal should be avoided unless a serious adverse event has occurred.

Reduce dose gradually over 4 weeks (except fluoxetine due to its long half-life), this is particularly important in drugs with a short half-life (e.g. paroxetine and venlafaxine).

Discontinuation symptoms (these can be drug specific, consult individual SPC for further information) include:

• Agitation
• Flu-like symptoms
• Headache
• Insomnia
• Irritability
• Shock-like sensations
• Vivid/excessive dreaming

Symptoms are usually mild and self-limiting but in some cases may be severe and prolonged.

Ensure patients are given adequate education on the symptoms they are likely to experience, onset and duration.

Cross-tapering is preferred when switching from one antidepressant to another:

• Dose of current antidepressant is reduced slowly while slowly introducing the new antidepressant
• Speed of cross-tapering should be based on individual patient tolerability
• Not suitable for all situations (see table for further information)

Risks associated with cross-tapering include:

• Pharmacodynamic interactions
• Serotonin syndrome
• Hypotension
• Drowsiness
• Pharmacokintetic interactions
  • Increased plasma levels of tricyclics by some SSRIs
• Antidepressant discontinuation symptoms
  • Could be mistakenly interpreted as side effects of new medication

Symptoms of serotonin syndrome include (see full guidance for management):

• Confusion
• Convulsions
• Myoclonus
• Restlessness
• Shivering

The table within the full guidance sets out guidance for specific drug to drug switches. Contact local clinical pharmacy services for additional advice.