Adverse reactions of selective serotonin reuptake inhibitors: reports from a spontaneous reporting system

The selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors (SSRIs) are extensively used in the treatment of depression, panic disorder and obsessive-compulsive disorder, and are now being evaluated in the treatment of a number of other psychiatric disorders. The aim of this study was to investigate the pattern of adverse reactions reported on SSRIs in Sweden and assess possible risk factors associated with the occurrence of adverse reactions to these agents.

A survey was made of 1202 reports describing 1861 adverse reactions to SSRIs submitted to the Swedish Adverse Drug Reactions Advisory Committee.

The most often reported adverse reactions were neurological symptoms (22.4%), psychiatric symptoms (19.5%) and gastrointestinal symptoms (18.0%); however, dermatological symptoms (11.4%) and general symptoms (9.8%) were also frequent. Compared with other drugs, gastrointestinal symptoms were more often reported for fluvoxamine, psychiatric symptoms were more often reported for sertraline and dermatological symptoms were more often reported for fluoxetine. In total, the diagnoses most frequently reported were nausea (n = 139), rash (n = 90), anxiety (n = 84), paraesthesias (n = 69), headache (n = 63) and diarrhoea (n = 63). Parkinsonism, confusion, hallucinations, euphoria, hyponatraemia, bradycardia and hypotension were more often reported in the elderly, whereas urticaria, akathisia, and haematological, endocrinological, sexual and some visual reactions were more often reported in individuals who were younger than average. Dermatological reactions, fatigue, hyponatraemia and cough were more common in women, whereas dyskinesias/akathisia and aggression more often were seen in men. The median SSRI dosages were above average in patients experiencing seizures, hypomania/mania, personality changes, malaise, bodyweight gain, gynaecomastia and hyperprolactinaemia/galactorrhoea. Severe symptoms, such as seizures, hyponatraemia and the serotonin syndrome, were rarely reported.

Although the design of the study makes it difficult to draw conclusions about causality, a variety of adverse reactions were reported. Therefore, the awareness that a particular symptom in a patient treated with an SSRI might be an adverse reaction should be high.