ANNOUNCER: Researchers discovered a very effective way of increasing the supply of dopamine.
C. WARREN OLANOW, MD: Dopamine itself doesn't get into the brain, so they came up with the idea of using levodopa. Levodopa does get into the brain, and it is converted in the brain to dopamine and creates astonishing benefits in many patients.
ANNOUNCER: However early attempts with levodopa produced difficult side effects, such as nausea and vomiting. Another enzyme in the body was breaking down the levodopa, causing these side effects. Researchers solved the problem by slowing the action of the enzyme.
C. WARREN OLANOW, MD: To try and prevent that from occurring, levodopa is typically administered with an agent that blocks its conversion to dopamine in the blood. The agent that we use mostly in the United States is called carbidopa, and typically levodopa and carbidopa are administered together.
ANNOUNCER: During treatment, patient's may get the feeling that the medication is wearing off and their symptoms begin to return.
WILLIAM KOLLER, MD: Wearing off is a response to medicine where the duration of response of an individual dose gets less over time. And the terminology we use is like a light switch. When you turn it on, you're well controlled by the drug and you're free of symptoms. When you're in the off state, all the symptoms come back, the tremor, the slowness, the stiffness, the difficultly walking.