Mirapex (pramipexole) is the first Parkinson’s agent approved by the FDA since Somerset’s monoamine oxidase inhibitor Eldepryl in 1989. Mirapex, a non-ergot D3 dopamine agonist, is approved for the treatment of the signs and symptoms of idiopathic Parkinson’s disease.
Efficacy was demonstrated in patients with early Parkinson’s disease who were not receiving concomitant levodopa therapy as well as in patients with advanced disease on concomitant levodopa. In a pivotal study in advanced Parkinson’s patients receiving levodopa, pramipexole reduced off hours from six hours per day to four hours per day. After a six-month maintenance period, symptom scores, as assessed by the Unified Parkinson’s Disease Rating Scale for daily living decreased by 2.7 points on a scale from zero to 52 in the pramipexole group, compared to 0.5 for the placebo.
Dopamine agonosts appear to impair the systemic regulation of blood pressure with resulting orthostatic hypotension. Patients appear to have an impaired capacity to respond to an orthostatic challenge.