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Selective Serotonin Reuptake Inhibitors (SSRI)

4.1. Gastrointestinal adverse effects

Woman with a stomach ache Very common and common adverse effects

SSRIs commonly cause dry mouth. Nausea, vomiting, and diarrhoea are also common with SSRIs and probably result from stimulation of serotonergic1 receptors in the gut; constipation can also occur.

Factors which increase risk

Gastrointestinal side effects increase with the dose. Drugs that raise the concentration of SSRIs (eg cimetidine with citalopram, escitalopram or sertraline) may increase the risk of side effects.


There is no specific treatment for gastrointestinal adverse effects of SSRIs. Nausea tends to improve within a few days. If unwanted effects do not subside over time and continue to be troublesome then dose reduction can be considered; alternatively, the antidepressant could be changed.

  1. A chemical agent (or synapse) that produces its effects via the serotonin transmitter system.