Dopamine agonists in the treatment of Parkinson disease

This study investigated the effectiveness of dopamine agonists in the treatment of Parkinson’s disease (PD). Researchers suggested that this treatment reduces physical movement symptoms, but increases other side effects.

PD is a disease associated with a variety of symptoms such as reduced movement capacity and balance, tremors and stiffness.

Treatments like levodopa are used to treat the symptoms. However, long-term treatment can be associated with movement complications, such as involuntary movement.

Dopamine agonists have also been used to treat PD. Prior studies showed that this treatment is associated with reduced symptoms. However, clinical effects are not well known. 

The objective of this study was to investigate whether dopamine agonists could be used instead of levodopa to treat PD.

This study reviewed 29 other studies and included information about 5247 PD patients. In these studies, patients were randomly assigned to receive dopamine agonists with or without levodopa, levadopa alone, or placebo (substance with no active effect).

Patients treated with a dopamine agonist were 49% less likely to develop dyskinesia (uncontrolled movements). These patients were also 36% less likely to have dystonia (muscle spasm) and 25% less likely to experience movement fluctuations (movement changes between medication doses).

However, patients treated with dopamine agonists were 3.68 times more at risk of edema (swelling of body parts), as well as other side effects such as sleepiness, constipation (difficulty in emptying the bowel), dizziness, hallucination and nausea.

This study showed that treatment with a dopamine agonist decreases movement symptoms but is associated with the increase of other side effects when compared to levodopa.

Further studies are needed to investigate the balance of risks and benefits of dopamine agonists.