Sinemet CR (carbidopa and levodopa) is a prescription drug, which is used for the treatment of Parkinson's disease and syndrome. Parkinson's disease is related to the nervous system that controls body movements. The disease is caused due to a lack of dopamine in the brain. If untreated, it could affect body movements and the patient might not be able to perform normal daily activities. Sinemet CR contains two active ingredients: carbidopa and levodopa. They are dopaminergic antiparkinsonian agents and thus reduce the symptoms of Parkinson's disease.