Serotonin toxicity association with concomitant antidepressants and rasagiline treatment: retrospective study (STACCATO).

BACKGROUND: The serotonin toxicity syndrome (STS) is a potential risk with concurrent use of the monoamine oxidase type-B inhibitor rasagiline and antidepressants.
OBJECTIVE: To assess systematically the occurrence of STS in patients with Parkinson disease (PD) treated with rasagiline plus antidepressants (R+ATD), rasagiline without antidepressants (R), or antidepressants plus anti-PD dopaminergic medications (ATD) other than either rasagiline or selegiline.
METHODS: A phase IV multicenter retrospective cohort study was conducted of patients with PD who began receiving R+ATD, R, or ATD between September 1, 2006, and December 31, 2008. Medical records were reviewed for patient demographics, treatment details, and hospitalizations/emergency department (ED) visits. An adjudication committee independently reviewed records to verify case ascertainment and used the Hunter Serotonin Toxicity Criteria for case definition. Outcome variables were analyzed by descriptive statistics.
RESULTS: A total of 1504 patients with PD (471 with R+ATD; 511 with R; and 525 with ATD) were enrolled from 37 sites. In the R+ATD and ATD groups, selective serotonin reuptake inhibitors (SSRIs) were most frequently used (74.5% and 77%, respectively). In the R+ATD and ATD groups, mean duration of antidepressant use (tricyclic, SSRI, and other) were 50.5-53.5 weeks and 51.7-80.9 weeks, respectively. Overall, 195 patients (13%) from all three groups had one or more hospitalization/ED visits. No cases of STS were identified in any group.
CONCLUSIONS: In this large multicenter retrospective cohort study, concurrent administration of R+ATD was not associated with STS. The findings of this phase IV study expand the drug interaction and pharmacovigilance safety awareness for the use of antidepressants in patients with PD.