Giving patients with Parkinson’s disease levodopa earlier than their clinical symptoms warrant provides no extra benefit, a Dutch study suggests.

The researchers set out to determine whether the drug worked merely by reducing symptoms, or whether it had a true disease-modifying effect.

Research in 2004 had been equivocal, on the one hand suggesting that levodopa might slow disease progression but also providing brain-imaging evidence suggesting treatment with the drug accelerated dopamine neuron degeneration.

In the current study 445 patients, mean age 64 years, diagnosed with early Parkinson’s disease (<2 years) and symptoms too mild to need treatment were allocated to either 100mg levodopa plus 25mg carbidopa three times daily or placebo for 40 weeks.