Starting Dopamine Agonist Treatment
Mr. Franks: "My Parkinson's disease is beginning to bother me and I need to start a medication. However, I would rather not start carbidopa/levodopa now. What are my alternatives?"
The primary alternatives to carbidopa/levodopa are the dopamine agonist drugs, primarily pramipexole (Mirapex.) or ropinirole (Requip). If symptoms are minimal, some physicians prescribe a minor drug such as selegiline, amantadine or an anticholinergic medication such as trihexyphenidyl (Artane).
Mrs. Good: "Which of the dopamine agonist drugs is best?"
There are four available dopamine agonist medications, bromocriptine (Parlodel), pergolide (Permax), pramipexole (Mirapex.), and ropinirole (Requip). The first two (bromocriptine and pergolide) are the oldest and now are prescribed much less frequently for two reasons:
- they are relatively expensive;
- they have unique, occasionally serious side effects. The other two dopamine agonists, pramipexole and ropinirole, are similar in efficacy and side effects. Pramipexole is a little easier to use because of the way the pills have been formulated.
Mr. Hall: "My doctor recommended starting pramipexole for my Parkinson's disease. How long can I stay on this before I need carbidopa/levodopa?"
People with PD eventually require carbidopa/levodopa and cannot be managed indefinitely with pramipexole or the other dopamine agonist drugs. When they require carbidopa/levodopa varies and depends primarily on the severity of PD. Typically people can be adequately managed on pramipexole alone for one to four years.
The dopamine receptor may be thought of as a lock that can only be opened with a specific key (dopamine). However, skeleton keys may also work and in this analogy, the skeleton keys are dopamine agonist drugs.
