To the Editor: Selective serotonin reuptake inhibitor (SSRI) and clomipramine discontinuation may cause dizziness, paresthesia, lethargy, nausea, vivid dreams, insomnia, headache, movement-related symptoms, crying spells, anxiety, agitation, and irritability R1564CHDGIHAH. Venlafaxine discontinuation can cause a similar syndrome R1564CHDGHFHC. The case of a patient showing discontinuation symptoms after withdrawal of clomipramine, ameliorated by fluoxetine, is presented. A MEDLINE search did not locate similar reports.

A sudden drop of synaptic serotonin levels may cause the discontinuation syndrome R1564CHDCFEBH. Clomipramine’s short half-life may be a risk factor R1564CHDCFEBH. Tricyclic antidepressant discontinuation syndrome (related to cholinergic rebound) does not usually include dizziness, which is more typical of SSRIs R1564CHDCCHBC. Other symptoms (nausea, vivid dreams, anxiety) may be related to clomipramine’s anticholinergic effects R1564CHDCFEBH. Fluoxetine, by increasing synaptic serotonin levels, may have prevented the reappearance of the clomipramine withdrawal symptoms. This argues against a cholinergic mechanism of the withdrawal syndrome. Fluoxetine’s long active metabolite half-life may have prevented a new withdrawal syndrome from developing after fluoxetine discontinuation R1564CHDCFEBH. Fluoxetine might be used to treat clomipramine discontinuation syndrome. It has been used during venlafaxine discontinuation R1564CHDJCBCB.