Fluoxetine for Clomipramine Withdrawal Symptoms
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 (1). Venlafaxine discontinuation can cause a similar syndrome (2). 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.
Mr. A, a 42-year-old man with major depressive and panic disorders, was in remission for 1 year with clomipramine, 150 mg/day, and clonazepam, 2 mg/day. He discontinued the dose of clonazepam over 3 months without problems. Then clomipramine was gradually discontinued over 3 weeks (112.5 mg/day for 7 days, 75 mg/day for 7 days, 37.5 mg/day for 7 days, then stopped). On the day after his last dose, he had dizziness, nausea, depressed mood, anxiety, sweating, and vivid dreams. Seven days later, with the symptoms persisting, the dose of clomipramine was restarted at 75 mg/day. His symptoms disappeared in 1 day. Two weeks later, clomipramine was discontinued again (37.5 mg/day for 5 days, then stopped), but it was replaced by fluoxetine, 20 mg/day, started 1 week before. After clomipramine discontinuation, Mr. A had no problems. One week later, fluoxetine was discontinued (10 mg/day for 5 days, then stopped). No discontinuation symptoms appeared during the following weeks.
A sudden drop of synaptic serotonin levels may cause the discontinuation syndrome (3). Clomipramine’s short half-life may be a risk factor (3). Tricyclic antidepressant discontinuation syndrome (related to cholinergic rebound) does not usually include dizziness, which is more typical of SSRIs (4). Other symptoms (nausea, vivid dreams, anxiety) may be related to clomipramine’s anticholinergic effects (3). 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 (3). Fluoxetine might be used to treat clomipramine discontinuation syndrome. It has been used during venlafaxine discontinuation (5).
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