Time until Need for Levodopa among New Users of Dopamine Agonists or MAO-B Inhibitors

OBJECTIVE: To investigate the use of dopamine agonists and monoamine oxidase type B (MAO-B) inhibitors in the Norwegian population, between 1 July 2006 and 31 December 2016. Our primary endpoint was time until need for levodopa among new monotherapy users of dopamine agonists and MAO-B inhibitors. METHODS: A prospective cohort study including all patients, aged 50 years or above, who had at least one prescription for a dopamine agonist or a MAO-B inhibitor dispensed in the study period. We used data from the Norwegian Prescription Database (NorPD). As we wished to focus on new Parkinson patients, we excluded patients who had levodopa dispensed less than 180 days prior to their first dopamine agonist or MAO-B inhibitor redemption. We explored the demographics and the time until monotherapy was insufficient treatment (defined as need for levodopa prescription). RESULTS: We included 22958 new monotherapy users. Of these, 22108 used dopamine agonists and 850 used MAO-B inhibitors. The mean number of days until the first prescription of levodopa was dispensed was higher among the dopamine agonist users (621 days) compared to the MAO-B inhibitor users (352 days). The proportion of dopamine agonist users who started levodopa treatment during the study period was less than 7%, while the corresponding proportion of MAO-B inhibitor users was almost 59%. CONCLUSIONS: We found that new dopamine agonist users had a much greater delay in the need for levodopa than new MAO-B inhibitor users. It seems to be beneficial to initiate treatment with dopamine agonists when starting pharmacological treatment for new Parkinson patients.