Association between use of antiemetics, antipsychotics, or antidepressants and the risk of Parkinson’s disease

Objective: Antipsychotics, antidepressants, and antiemetics are well-known causative agents of parkinsonism. However, it is not certain that the use of these medications increases the risk of Parkinson’s disease (PD). We aim to define the risk of PD associated with use of antipsychotic, antidepressant, or antiemetic therapy. Materials and methods: We conducted a population-based nested case-control study using data from the South Korean health insurance database. For each PD case, we randomly selected sex, age group, cohort entry date, duration of followup, and Charlson comorbidity score-matched controls (up to 3). Exposure was categorized into six groups based on treatments received 1 – 90 days before the index date (separate use of either: antiemetics; antipsychotics; or antidepressants; combined use of antiemetics with either: antipsychotics; or antidepressants; and combined use of all three). We used conditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for PD. Results: Final subjects included 31,428 cases and 94,284 matched controls. We observed an increased risk of PD with the separate use of antiemetics (adjusted OR, 1.08; 95% CI, 1.05 – 1.11) and that of antipsychotics (1.31; 1.12 – 1.52), and the combined use of antiemetics and antipsychotics (1.42; 1.15 – 1.75). Both antidepressants alone and with antipsychotics were not associated with higher risk of PD. Conclusions: Separate or concurrent use of antiemetics and antipsychotics showed increased risks of PD. Although statistical significance was observed, when taking into account that there still lie unmeasured, unconsidered confounders, there may be no clinical association present. Caution will be needed in prescribing these drugs in patients who have prognostic factors for PD.