Key takeaways

  • Oral medications are often the first treatment for Parkinson’s disease. They work by increasing dopamine levels or mimicking dopamine’s effects, but symptom control may change over time.
  • Infusion therapies deliver medication continuously, which can reduce symptom fluctuations and offer more consistent control, especially in later stages of Parkinson’s.
  • Choosing a treatment depends on symptoms, disease progression, treatment response, daily routines, and personal preferences. Talking through all options with your healthcare team can help guide the decision.

Parkinson’s disease is a progressive condition that affects how the brain controls movement. It develops when changes in the brain disrupt the nerve cells that help coordinate motion.

As the condition progresses, damage to these nerve cells can lead to symptoms such as tremors, muscle stiffness, slowed movement, and changes in balance or coordination. Symptoms often evolve over time, which can affect how well different treatments work.

Medications play a central role in managing Parkinson’s symptoms. These treatments may be taken by mouth or delivered via infusion. The best option depends on a person’s symptoms, how their body responds to treatment, and how treatment fits into their daily life.

Oral medications are those you take by mouth. In Parkinson’s disease, many oral medications fall under what’s known as “dopaminergic therapy,” which is often the first treatment approach. These medications work by replacing dopamine or mimicking its effects in the brain.

Parkinson’s disease affects cells that produce dopamine, a chemical that helps coordinate movement. When dopamine levels drop, the brain has a harder time sending clear signals to the muscles. This can lead to symptoms such as stiffness, slowed movement, tremors, or difficulty with coordination.

While dopaminergic therapy is a mainstay of Parkinson’s treatment, not all oral medications work the same way.

Some target other brain chemicals (neurotransmitters) involved in movement or non-motor symptoms, offering additional options when dopamine-based treatments alone aren’t enough.

Dopamine precursor

A dopamine precursor is a medication that the brain converts into dopamine. This helps replace some of the dopamine lost as Parkinson’s disease affects dopamine-producing cells. As dopamine levels increase, movement-related symptoms may improve.

Levodopa is the most commonly prescribed dopamine precursor for Parkinson’s and remains a key treatment option for many people.

COMT inhibitors

Catechol-O-methyltransferase (COMT) inhibitors help levodopa work longer in the body. They do this by blocking an enzyme that breaks down levodopa before it reaches the brain. When more levodopa stays active, symptoms may stay better controlled between doses.

Doctors prescribe COMT inhibitors alongside levodopa, not on their own. These medications can help reduce “wear-off,” which is when symptoms return before the next dose is due.

Common COMT inhibitors include:

  • entacapone
  • opicapone
  • tolcapone

Dopamine agonists

Dopamine agonists stimulate dopamine receptors in the brain. While they aren’t dopamine themselves, they mimic its effects to help manage movement-related symptoms.

These medications tend to last longer in the body than levodopa, but may not be as strong at controlling symptoms. In some cases, doctors may use dopamine agonists earlier in treatment alongside levodopa to help ease symptom control.

Common dopamine agonists include:

  • pramipexole
  • ropinirole

MAO-B inhibitors

Monoamine oxidase (MAO) inhibitors help existing dopamine last longer in the brain. They work by blocking an enzyme that normally breaks down dopamine, allowing it to remain active for a longer period.

These medications may be used alone in early Parkinson’s disease or added to other treatments to help reduce symptom fluctuations.

Common MAO-B inhibitors include:

  • selegiline
  • safinamide
  • rasagiline

Decarboxylase inhibitors

Decarboxylase inhibitors help protect levodopa as it travels through the body. They block the enzyme decarboxylase, which breaks down levodopa outside of the brain. This allows more of it to reach the brain where it’s needed.

Doctors prescribe these medications alongside levodopa, not on their own.

Common decarboxylase inhibitors include carbidopa.

Adenosine A2A antagonists

Adenosine A2A antagonists work by blocking receptors that interfere with dopamine signaling. By reducing this interference, these medications can help enhance dopamine’s effects and improve movement-related symptoms.

Doctors may add these medications to other Parkinson’s treatments, particularly when “off” periods become more noticeable.

Common A2A agonists include istradefylline.

Anticholinergics

Parkinson’s disease affects more than just dopamine. As dopamine levels drop, another brain chemical called acetylcholine can become more active. This imbalance may contribute to symptoms such as tremors and muscle stiffness.

Anticholinergics block acetylcholine activity, which may help reduce these symptoms.

Common anticholinergics include:

  • benztropine
  • trihexyphenidyl

Infusion medications for Parkinson’s are delivered continuously through a small pump system that’s been surgically implanted. Doctors may recommend infusion medications when:

  • oral medications aren’t enough to manage symptoms
  • symptoms return between oral doses
  • side effects from long-term oral medication use become difficult to manage

Unlike oral medications, infusion therapies provide a steady dose of medication throughout the day. This can help reduce “off” time and smooth out symptom fluctuations for some people.

Currently, three infusion therapies are available for Parkinson’s disease:

  • Duopa (levodopa-carbidopa intestinal gel): This therapy combines a dopamine precursor with a decarboxylase inhibitor and delivers the medication directly into the small intestine through a surgically placed tube connected to a pump.
  • Onapgo (apomorphine infusion): This dopamine agonist is delivered through a small pump under the skin (subcutaneous infusion).
  • Vyalev (foslevodopa/foscarbidopa): This combination of a dopamine precursor and a decarboxylase inhibitor is also delivered through a pump under the skin (subcutaneous), providing steady medication levels throughout the day.

Oral medications and infusion therapies for Parkinson’s disease may use similar types of drugs, but they differ in how they’re delivered, how steadily they work, and how they affect day-to-day routines.

Oral medications

Oral medications are taken by mouth and absorbed through the digestive system. Medication levels in the body rise and fall with each dose, which works well for many people, especially earlier in treatment.

Over time, some people experience “wearing off.” This happens when symptoms return because the next dose is due, often because the brain no longer responds to the medication as consistently as it once did.

Long-term levodopa use and fluctuating dopamine levels may also increase the risk of dyskinesia. Dyskinesia refers to involuntary movements that can occur when dopamine receptors become overstimulated.

Infusion therapies

Infusion therapies deliver medication continuously through the day, helping keep drug levels more steady. This steady delivery helps reduce “off” periods and makes symptom control more consistent for some people.

Because infusions don’t rely on digestion, they tend to work more predictably regardless of gut health. However, they require a pump system, which involves a surgical procedure and ongoing maintenance.

Dyskinesia may occur less often with infusion therapy; however, it can still happen in some cases.

Due to factors such as cost, surgery, and daily management, doctors usually reserve infusion therapies for people with more advanced Parkinson’s disease when oral medications no longer provide enough symptom control.

Both oral medications and infusion therapies can play an important role in managing Parkinson’s disease. The best option often depends on symptom patterns, treatment response, lifestyle considerations, and personal preferences.

Learning about different medication differences can be empowering. It’s a way you can partner with your healthcare team and be an active participant in deciding your treatment plan.

To help guide this conversation with your doctor, consider these tips:

  • Prepare for your appointment ahead of time. Keep a symptom journal and track how you feel throughout the day while taking your current medications.
  • Write things down. Bring a list of questions and concerns you want to discuss.
  • Clarify your goals. Think about what you’d like to improve, such as reducing “off” time, managing side effects, or maintaining daily activities.
  • Define your preferences for treatment. Let your care team know what feels right for you. It’s OK to say if you’re not comfortable with surgery, for example.
  • Ask about your current treatment. Find out why your medications were chosen and what other options may be available.
  • Bring support if helpful. A loved one can help take notes or ask questions during the appointment.
  • Discuss all considerations. Talk through the benefits, risks, convenience, and potential costs of each treatment.

Medications for Parkinson’s disease may be taken by mouth or delivered through infusion. The option that works best for you often depends on your symptoms, how Parkinson’s changes over time, and what fits your preferences and daily life.

It’s OK to ask your doctor about other treatment options, especially if your current plan doesn’t fully manage your symptoms. Preparing for appointments with written questions or concerns can help you make the most of your conversations and feel more confident in treatment decisions.