Faulty metabolism of Parkinson's medication in the brain linked to severe side effects

Until now, the reason why the drug levodopa (L-Dopa), which reduces the motor symptoms of Parkinson's disease, declines in efficacy after a few years' use has been unknown. A side effect that then often occur is involuntary movements. Scientists have now been able to connect the problems with defective metabolism of L-Dopa in the brain.