Sinemet combines two drugs together which are cardibopa and levodopa. This combination, known as Sinemet is prescribed by doctors to address symptoms of Parkinson's disease. Many doctors are of the opinion the lack of a naturally occurring substance known as dopamine causes this debilitating condition. Levodopa is converted to dopamine in the brain, and this aids in controlling the movements. Cardibopa prevents the breakdown of levodopa so that most of it gets to the brain.