Levodopa also known as levocarb and co-careldopa, is the combination of the two medications carbidopa and levodopa. It is primarily used to manage the symptoms of Parkinson's disease but does not change the course of the disease. It is taken by mouth. It can take two to three weeks of treatment before benefits are seen. Each dose then begins working in about ten minutes to two hours with duration of effect of about five hours. Common side effects include movement problems and nausea. More serious side effects include depression, low blood pressure with standing, sudden onset of sleepiness, psychosis, and increased risk-taking behavior. Carbidopa prevents the breakdown of levodopa outside the brain. In the brain, levodopa is broken down into dopamine by which it has its effects. Carbidopa also helps prevent some of the nausea which levodopa causes.