Dopamine agonists reduce motor complications in Parkinson's disease, but increase other side-effects

Dopamine agonists are increasingly used to treat people with Parkinson's disease, but there is a debate about how well they work.

A review of current data indicates that there is less risk of developing motor complications with these drugs. However, the review revealed that dopamine agonists can also lead to a range of other side-effects, including oedema, sleepiness, constipation, dizziness, hallucinations and nausea.

This is the first review that assesses dopamine agonists as a class. The researchers found 29 eligible trials that included a total of 5247 participants.

"When you consider costs, benefits and side-effects, the old drug levodopa is probably still the best option, although we can't be sure because few studies asked patients how the drugs affected their overall quality of life," says lead researcher Dr Rebecca Stowe who works at the University of Birmingham Clinical Trials Unit, in Edgbaston, Birmingham.

"To clarify the balance of risks and benefits, we're running a large study called PD MED that is assessing patient-rated quality of life and economic measures," says Stowe.