Antidepressants generally take up to 4 weeks of initiation for clinically noticeable improvement.

All patients:

• Review 2-4 weeks after initiation

Patients 18-25 y/o or those at risk of suicide:

• Review 1 week after initiation or increasing the dose (due to the initial increased risk of suicidal ideation)

Only consider stopping after remission:

• Continue for at least 6 months after remission (same dose) (~12 months in elderly)
• If antidepressants used for generalised anxiety disorder → continue at least 12 months (as likelihood of relapse is high)

The dose should preferably be reduced gradually over 4 weeks, or longer if withdrawal symptoms emerge (6 months in patients who have been on long-term maintenance treatment).

Important adverse effects:

• Increase risk of suicidal ideation in early weeks of treatment
• Risk of withdrawal symptomsMost commonly experienced withdrawal reactions: - Dizziness - Paraesthesia - GI disturbances (esp. nausea and vomiting) - Headache - Sweating - Anxiety - Sleep disturbances if abruptly stop / miss dose / do not take a full dose (may occur within 5 days)
  • Paroxetine and venlafaxine has the highest risk
• Hyponatraemia (especially SSRIs)

  Most antidepressants can be switched directly (i.e. no overlap or drug-free period), with 2 notable exceptions:

• Switching fluoxetine into SSRI / TCA / venlafaxine:
  • First taper fluoxetine dose slowly
  • Then, 4-7 days of drug-free period
  • Lastly, start the new drug at low dose and titrate up

 

• Switching from SSRI into TCA, use cross-tapering:
  • First taper SSRI dose slowly
  • Then, at the same start and increase low-dose TCA 

SSRIs and SNRIs can cross the placenta and have potential effect on the fetus.

Choice of antidepressant in pregnancy: SSRIs (as it has the most pregnancy safety data)

• If patient plans to breastfeed, sertraline and paroxetine might be preferred
• If patient is already stable on current treatment, that is not SSRI, risk of destabilisation must be taken into account.

Recognised risk outlined by MHRA and NICE CKS:

• Persistent pulmonary hypertension in the newborn (PPHN)- Background risk: 1-2 per 1,000 pregnancies - Risk with maternal SSRI use: 5 per 1,000 pregnancies
• Neonatal withdrawal and serotonergic effectsMay occur if SSRIs / SNRIs are used until or shortly before birth: - Difficulty in sucking / sleeping - Irritablity - Tremor - Muscle weakness - Persistent crying  
• Postpartum haemorrhage (if used in the month before delivery)
• Some studies show an association between SSRI use in pregnancy and an increased risk of miscarriage

 

Sertraline and paroxetine are generally the SSRIs of choice for treatment initiated in breastfeeding women.