Switching antidepressant (SSRIs to monoamine oxidase inhibitors (MAOIs)) in adults

SSRIs to monoamine oxidase inhibitors (MAOIs)

• switching to an MAOI is always a complex switch and you should follow specialist advice

Taper, washout and switch with specialist advice

• for any SSRI, you should gradually reduce the dose and stop
• a clinician will then need to wait for a period (see below), dependent on the antidepressant being switched from, before starting the MAOI
  • the specialist will advise the duration of the washout period on a case-by-case basis taking into consideration the MAOI being started.

Cross-tapering is not recommended due to the high risk of serotonin syndrome.

From all except fluoxetine

• after stopping the SSRI, wait 7 to 14 days before starting the MAOI

From fluoxetine

• after stopping fluoxetine, wait 5 to 6 weeks before starting the MAOI
• fluoxetine may still cause medicine interactions 5 or 6 weeks after stopping, as fluoxetine and its active metabolite have a long half-life

Reference:

• NHS Specialist Pharmacy Service (February 2023). SSRIs to other antidepressants: switching in adults