Requip xl is a much stronger drug with more , potentially serious, side effects, but also greater efficacy on symptoms. Younger patiens tolerate the side effects better. The starting drug is usually the preference of the individual neurologist. A PD nurse told me she could immediately tell who someone's consultant was by their medication. Of the dopamine agonists the choice is nowadays more often Requip than Mirapexin, but a few years ago these were both prescribed in equal numbers. Like some patients are started on Sinemet, others on Madopar, both levodopa drugs. And there are a few neurologists, who hope that Azilect will eventually prove to be neuroprotective after all.