What Are Dopamine Agonists?
Dopamine agonists are a class of drug used to treat the symptoms of Parkinson’s disease (PD). Carbidopa-levodopa therapy is the most effective drug available to treat the motor symptoms of PD. However, other drugs like dopamine agonists may be used first to avoid some of the side effects seen with levodopa-carbidopa therapy. Dopamine agonists may also be used along with carbidopa-levodopa therapy.1
Dopamine agonists are effective in reducing the motor fluctuations seen in many people with PD. People treated with carbidopa-levodopa with fluctuating symptoms of PD are described as having “on” and “off” episodes. "On" episodes describe when the medicine is working and symptoms are minimal. "Off" episodes are when the medicine has not yet taken effect or is wearing off and symptoms are worsened. "Off" episodes can interfere with daily activities and may be experienced many times a day. They may last a few minutes or as long as a few hours.1,2
How do dopamine agonists work?
Symptoms of PD, especially motor symptoms, are related to a depletion of dopamine in the brain. Dopamine is the neurotransmitter (chemical messenger) that is responsible for producing smooth, purposeful movement. Giving dopamine as a treatment is ineffective because it cannot cross the blood-brain barrier.3
Dopamine agonists mimic dopamine. They bind to proteins on neurons called dopamine receptors. Dopamine agonists can be designed to bind to and activate specific dopamine receptors on neurons. This provides relief from symptoms of PD, especially motor symptoms like:3
Examples of dopamine agonists
Several different dopamine agonists are used to treat PD, including:3
- Apokyn™ (apomorphine hydrochloride) injection
- Neupro® (rotigotine) transdermal system patch
- Mirapex® (pramipexole dihydrochloride) tablet
- Mirapex® (pramipexole dihydrochloride) extended-release tablets
- Requip® (ropinirole) tablet
- Requip® XL™ (ropinirole) extended-release tablets
- Kynmobi® (apomorphine hydrochloride) sublingual film
People with PD may be prescribed different dosages at different points in their disease to manage their symptoms.
Side effects can vary depending on the specific drug you are taking. The most common side effects of dopamine agonists include:3,4
- Hallucinations (seeing or hearing things that are not real)
- Sudden sleepiness (sleep attacks)
- Dizziness or light-headedness
Dopamine agonists may also cause dyskinesia, or sudden and uncontrollable movements. Although dopamine agonists are less likely to cause dyskinesia than carbidopa-levodopa therapy, dyskinesias can greatly affect a person’s quality of life.3,4
A less common side effect of dopamine agonists is impulse control behaviors. Examples include increased gambling urges, increased sexual urges, or other intense urges.3,4
These are not all the possible side effects of dopamine agonists. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with dopamine agonists.
Things to know about dopamine agonists
It is important for people with PD to see a movement disorders specialist who is trained in the use of these drugs for PD. They understand the interactions of these drug and how some medicines may make symptoms worse.
It is important to know that delaying or stopping PD medicines will affect symptoms and can also be dangerous. For example, missing a dose of a dopamine agonist may lead to withdrawal symptoms like anxiety or pain.3
Before beginning treatment for Parkinson's disease, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.
Besides dopamine agonists, there are several different types of treatment for the symptoms of PD, including:1
Each person with PD experiences a unique set of symptoms and progression of the disease. Treatments are based on the person's symptoms and how they respond to different drugs.1