Sinemet® CR (
carbidopa-levodopa CR) is a prescription medication most frequently used to treat
Parkinson's disease. This medication is also approved to treat
Parkinsonism (Parkinson-like symptoms) due to
encephalitis (inflammation or infection of the brain), manganese poisoning, or carbon monoxide poisoning. Sinemet CR is specially designed to slowly release the medication over four to six hours, helping to prevent fluctuations in the level of
carbidopa and levodopa in the blood.
Sinemet CR is marketed by Bristol-Myers Squibb Company and made by Merck & Co., Inc.
How Does Sinemet CR Work?
Sinemet CR contains two different active ingredients, levodopa and carbidopa. The levodopa is the "real" ingredient in Sinemet CR that works for Parkinson's disease. The carbidopa does not have any direct effects on Parkinson's disease when used alone, but it does help to make the levodopa more effective.
Dopamine deficiency (caused by a loss of dopamine-producing cells) in certain parts of the brain may be responsible for many of the symptoms of Parkinson's disease. Although it would make sense to give dopamine to help treat Parkinson's, this does not work, as dopamine cannot cross the blood-brain barrier to reach the brain. Levodopa is a precursor of dopamine, which means that the body can use levodopa to make dopamine. Unlike dopamine, levodopa crosses the blood-brain barrier.
Levodopa is almost always given in combination with carbidopa. Carbidopa delays the conversion of levodopa into dopamine until it reaches the brain, preventing or diminishing some of the side effects that often accompany levodopa therapy. Carbidopa also reduces the amount of levodopa needed for
Parkinson's disease treatment.
