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INTRODUCTION The aim was to determine the time elapsed between the start of treatment with antiparkinsonian agents and the modification of the pharmacological therapy, and to establish its related factors, in a group of patients with Parkinson's disease from Colombia. PATIENTS AND METHODS Retrospective cohort study that collected information about the treatment of patients with Parkinson's disease who started drug therapy between June, 2011 and December, 2013; a five-year follow-up was performed. Survival analyses for time to therapy modification were generated, and factors related to these changes were determined using Cox regression models. RESULTS A total of 3,224 patients (51.8% men) with a mean age of 73.1 ± 13.5 years started treatment with antiparkinsonian agents. After five years, 2,046 patients (63.5%) had modifications in drug therapy, in a mean time of 36.4 months (95% confidence interval: 35.7-37.1). A total of 1,216 patients (37.8%) required the addition of another active principle, while 830 (25.7%) had a switch to another drug. In the multivariate analysis, male sex, age over 65 years, and the start of amantadine were identified as factors that increased the likelihood of therapy modification. The use of bromocriptine, biperiden, and monotherapy as an initial treatment were associated with a reduction in this likelihood. CONCLUSIONS After five years of treatment, 63.5% of the patients with Parkinson's disease required modifications to their therapy, with a mean time of three years. Male sex, age over 65 years, and receiving initial therapy with amantadine affected the likelihood of switching therapy in these patients in Colombia.