Is there any antidepressant known to cause less gastrointestinal side effects such as diarrhea comp

Fråga: Is there any antidepressant known to cause less gastrointestinal side effects such as diarrhea compared with others? A selective serotonin reuptake inhibitor (SSRI) is primarily considered. A 75-year-old man has irritable bowel syndrome. Because of depression treatment with fluoxetine 20 mg daily was started. After two weeks the drug was withdrawn because of frequent loose stools. Previous treatment with sertraline was stopped due to the same problem. Moclobemide up to 600 mg daily was without benefit. Also, the antidepressive effect of the latter was insufficient.

Sammanfattning: Diarrhea seems to be less commonly reported for citalopram compared with the other SSRIs. In this patient a higher dose of moclobemide may be tried before considering a switch to citalopram. As an alternative, treatment with a tricyclic antidepressant may be considered.

Svar: For all SSRIs diarrhea has been reported as a relatively common side effect. About 10-20% of patients initiated on SSRI therapy will experience diarrhea (1). It has been suggested that treatment with sertraline and fluoxetine is more frequently associated with diarrhea or loose stools compared with citalopram and paroxetine (1,2). In a study including 217 patients, citalopram induced fewer gastrointestinal adverse events compared with fluvoxamine treatment (3). In another study sertraline treatment was associated with higher gastrointestinal side effects compared with citalopram treatment (4). A review article states that fluvoxamine and paroxetine had more gastrointestinal reactions than the other SSRIs during their first two years of marketing (5). In the Swedish adverse drug reaction register 17 out of 117 reports of gastrointestinal side effects concerns diarrhea during citalopram treatment. The corresponding numbers for fluoxetine are 5/20, paroxetine 19/105, fluvoxamine 14/88 and sertraline 18/47. The number of reports should be related with the sales figures of each drug for a relevant comparison. Among all SSRIs, citalopram is the most widely used drug in Sweden. Taken the sales figures of each drug into account, there is a tendency for citalopram causing less gastrointestinal side effects such as diarrhea compared with the other SSRIs.

For non-responders on moclobemide treatment, it might be worthwhile to try a higher dose of 750 to 900 mg daily.

Concerning gastrointestinal side effects, anticholinergic effects such as constipation are rather common during treatment with tricyclic antidepressants (6). If the present patient has diarrhea as a dominant symptom of irritable bowel syndrome tricyclics might be an alternative.