Levodopa is used to treat many of the symptoms experienced by the 10 million people with Parkinson’s. The drug works by passing the blood-brain barrier and releasing dopamine in the brain.
But some of the drug is converted to dopamine before it gets there, which can cause adverse side effects and limit the drug’s effectiveness. A particular problem is that the drug is broken down by enzymes in the gut and blood vessels. For this reason, people with Parkinson’s usually take levodopa in combination with another drug, carbidopa, that inhibits the break down.
