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Home / Living with Parkinson’s / Medication side effects

Parkinson’s medication: Treatment options and side effects 

Medication is the primary treatment for Parkinson’s. The medications used to treat Parkinson’s works to restore dopamine in the brain to a more normal level, in order to address motor symptoms. It’s important to take prescribed Parkinson’s medications on time, every time.

Your medication will be reviewed over time to make sure you receive the best combination for you as your condition progresses.

You may need to be careful if you take medication for other reasons. Your GP, pharmacist or specialist can advise on this.

There are many different medications prescribed for Parkinson’s. None are perfect, however research into treatments is improving the options all the time.

Every person with Parkinson’s has a different experience of the condition. Your GP or specialist will aim to find the best treatment for your needs.

We’ve made every effort to ensure that the information presented below is accurate at the time of updating. Please remember that information about medications may change. This website does not list all the uses and side effects associated with these medications.

We advise you to speak to your GP or specialist about your individual healthcare.

Common medication treatments for Parkinson’s

Levodopa is the main treatment for Parkinson’s. It works by converting into dopamine in the brain. Levodopa medications contain other drugs. Levodopa can be used at all stages of Parkinson’s and always has an effect on Parkinson’s symptoms.

  • Co-beneldopa (Madopar, Madopar CR)
  • Co-careldopa (Syndopa, Sinemet, Sinemet CR, Kinson)
  • Intra jejuneal Co- careldopa (Duo dopa intestinal gel,)
  • Duo-dopa intestinal gel (delivered by a tube surgically placed into the stomach/jejunum)
  • Co-careldopa plus entacapone (Stalevo)

Levodopa is given with benserazide or carbidopa, to make sure it can enter the brain more efficiently. Stalevo also contains entacapone which assists the medication to last longer by blocking the COMT enzyme which blocks the breakdown of dopamine.

Levodopa and protein 

Taking levodopa with food can sometimes help to reduce feelings of sickness. However, for some people, protein (found mainly in meat, fish, eggs, cheese, and beans) seems to interfere with the effectiveness of the medication by stopping how well it’s absorbed by the body. 

This may mean the drug is less effective if taken with, or after, a protein-rich meal. 

Some people may benefit from taking their medication at least 30 minutes before they eat. This is not a concern in early Parkinson’s but becomes more important when you have had Parkinson’s for some time and may be experiencing ‘wearing off’. 

As protein is essential for a healthy diet, you should speak to your GP or specialist before you make any changes. They can advise you on timing your dose and can help you to get advice from a registered dietitian. 

Side effects and problems with levodopa 

When you begin taking levodopa, you may feel sickness or nausea. In most people this will pass as your body adjusts to the medication. 

As Parkinson’s progresses over time, the levodopa dose will need to be adjusted. Many people will become more aware that symptoms sometimes return between doses of medication. This is called ‘wearing off’ and is a sign that your dose needs to be adjusted. 

As levodopa is absorbed through the gut, constipation or other stomach problems may impact on uptake of the medication. Extra involuntary movements (dyskinesia) can occur in some people who’ve had Parkinson’s for some time. Your neurologist will be able to help adjust medications to minimise dyskinesia. 

Other side effects may include: 

  • Mood swings 

Side effects of levodopa can sometimes be improved by changing your dose, the form of the drug or how often you take it. If this doesn’t work, other types of drugs may be combined with levodopa. 

Speak to your GP or specialist about the right treatment for you. 

Most people can take Madopar, Sinemet and Kinson without experiencing sickness or nausea and will experience considerable long-term improvement, especially in stiffness and slowness of movement.

Treatment will usually start on a low dose. This is gradually increased until you and your GP or specialist agree that your symptoms are under control.

Madopar is available in capsules, which should not be broken, scored tablets which can be broken or dispersible tablets, which can be dissolved in water. Sinemet can be taken in pill form. Both Madopar and Sinemet come in different strengths, depending on the dose your GP or specialist thinks you need. Kinson comes in one tablet which is scored.

Controlled release Madopar and Sinemet 

Controlled release preparations have the letters CR or HBS after the drug name. 

These let the levodopa enter your body slowly instead of all at once. They can increase the time between doses. 

They may be used when the dose of standard levodopa starts to wear off and the person taking it no longer feels the treatment is effective. 

Controlled release options can sometimes reduce involuntary movements (dyskinesia). 

Dispersible Madopar 

Madopar has a dispersible, or dissolvable, form that may be swallowed whole or dissolved in water. 

It takes effect more quickly because it doesn’t need to be broken down in your stomach to release the active ingredient. This may be a good option at the start of a day to provide a ‘kick start’ or if you experience ‘wearing off’. 

Non-dispersible tablets or capsules should not be crushed and put into water. 

Duodopa is a gel that is pumped continuously through a tube that is inserted into the intestine, where it’s absorbed through the gut into the bloodstream. 

This option is suitable for a small number of people, who have had Parkinson’s for some time and whose symptoms can’t be controlled with more common treatments. 

Because it’s given continuously, if you are prescribed duodopa you’re less likely to experience involuntary movements. You might have fewer ‘off’ periods. And it may also help you control your symptoms at night. 

Stalevo combines levodopa with carbidopa and entacapone in one tablet. 

Dopamine agonist medications make the cells that use dopamine work more efficiently. They have a longer-lasting effect than levodopa and can be used with levodopa to help it to work for longer.  

  • Bromocriptine (Parlodel) 
  • Cabergoline (Cabaser) 
  • Pramipexole (Sifrol, Sifrol SR) 
  • Rotigotine (Neupro Patch) 
  • Apomorphine (Movapo, Apomine). 

Dopamine agonists are used at all stages of Parkinson’s. You might take them alone when treatment is being started, or alongside levodopa to help it work better. 

Treatment with dopamine agonists has to be started carefully, with the dose gradually increased until you and your specialist are happy that your symptoms are under control. 

Taking dopamine agonists 

While dopamine agonists are introduced gradually, benefits begin to appear as dosage is increased.  

Research has shown they can also have a good effect on the non-motor symptoms of Parkinson’s. 

Dopamine agonists come as tablets or patch (Rotigotine) capsules or as an injection (Apomorphine)  

Some dopamine agonist tablets are now being made as ‘one-a-day’ tablets, or as prolonged-release tablets. These work for longer in the body compared to normal capsules and tablets. 

Side effects and problems with dopamine agonists 

Common side effects of dopamine agonists include: 

If you’re taking Cabergoline (Cabaser), or Bromocriptine (Parlodel) your neurologist or GP will have to arrange a chest CT scan or ultrasound of your heart yearly as over time these medications may affect heart or lung tissue. 

This precaution does not apply to the other dopamine agonists available in Australia. 

Dopamine agonists and impulsive and compulsive behaviour 

Some people taking dopamine agonists may experience problems with impulsive or compulsive behaviours. For example, an increased desire to gamble or engage in sexual activity. These behaviours often develop slowly so may not seem to be a problem immediately. It’s important for both the person with Parkinson’s and their family to be aware of this side effect. If affected, a reduction in dose or stopping the medication will stop the behaviour. 

MAO-B inhibitors are used to treat the symptoms of Parkinson’s. 

They prevent the breakdown of the chemical messenger dopamine in the brain, by blocking an enzyme that breaks it down, called monoamine oxidase type B (MAO-B). 

They are used to make the drug levodopa last longer or reduce the amount required. 

The generic drug names and brand names are: 

  • Rasagiline (Azilect) 
  • Safinamide (Xadago) 
  • Selegiline (Eldepryl, Zelapar). 

Advantages of MAO-B inhibitors 

A MAO-B inhibitor can be used on its own in early Parkinson’s, or in combination with other drugs at all stages of Parkinson’s. 

These drugs are available as tablets. There is also a form that dissolves on the tongue, which may help if you have trouble swallowing. 

MAO-B inhibitors may reduce fluctuations in the effectiveness of drugs that some people with Parkinson’s experience after the first few years. 

By itself, selegiline has very few side effects. 

Because Zelapar is absorbed better, a smaller dose is needed. 

Disadvantages of MAO-B inhibitors 

When selegiline is taken together with levodopa, side effects such as dyskinesia (involuntary movements), hallucinations or vivid dreaming may sometimes occur or worsen. 

When taken with levodopa, the most common reports have been of uncontrolled movements and accidental falls. 

Many of these side effects may be due to the increase in dopamine caused by rasagiline or selegiline. Your doctor or consultant can alter the dosage to correct these effects.  

MAO-B inhibitors may interact with other medications including some types of antidepressants, herbal supplements and food containing tyrosine – typically mature cheese. You may not be able to take MAO-B inhibitors, as these drugs or tyrosine can interact with each other to raise blood pressure to a dangerous level. 

Your neurologist or pharmacist is the best person to advise on potential interactions with other medications. 

COMT inhibitors are used to treat the symptoms of Parkinson’s. They must be used with levodopa because they don’t help Parkinson’s on their own. 

COMT inhibitors reduce Parkinson’s symptoms by blocking an enzyme that breaks down levodopa, prolonging its effect. There are branded and unbranded COMT inhibitors available. These include: 

  • Entacapone (Comtan) – can be taken with levodopa. It’s effective from the first dose and you should feel the benefit within a day or two. 
  • Opicapone (Ongentys) – taken once a day, usually at bedtime. It’s effective from the first dose, with benefit felt within a day or two. 

Advantages of COMT inhibitors 

When used with levodopa, COMT inhibitors can reduce the daily ‘off’ time and increase the ‘on’ time. In many cases, the dose and frequency of levodopa can also be reduced. 

The terms ‘on/off’ or ‘motor fluctuations’ refer to the period when people can no longer rely on the smooth and even symptom control that their drugs were giving them. 

Disadvantages of COMT inhibitors 

These drugs can increase the side effects caused by levodopa, notably dyskinesia (involuntary movements), nausea and vomiting. 

If these side effects increase after starting the drug, people should raise the issue with their GP or specialist, as reducing the levodopa dose can often help. 

Entacapone will discolour urine making it a reddish-brown colour. Some people also experience diarrhoea which may occur some months after commencing the medication.  

Opicapone may cause constipation, light headedness and, more rarely, hallucinations or aggression. 

Be aware that other drugs for Parkinson’s or other conditions can affect the action of COMT inhibitors. The combination of apomorphine and entacapone needs careful supervision. 

Anticholinergics are a type of drug, less commonly prescribed now, used to treat the symptoms of Parkinson’s. 

They block the action of acetylcholine, a chemical messenger that helps to send messages from your nerves to your muscles. 

There are branded and unbranded anticholinergics available. These include: 

  • Benztropine (Benztrop) 
  • Trihexyphenidyl (Artane). 

Anticholinergics may be useful in the early stages of Parkinson’s when symptoms are mild. They tend to improve tremor more than slowness and stiffness. 

They can be prescribed alone in the early stages, before levodopa is necessary. They can be used in conjunction with levodopa or a glutamate antagonist too. 

Anticholinergics can be used to reduce excess saliva. 

They can also reduce bladder contractions that can cause a strong, frequent urge to urinate. The action of anticholinergics is similar to that of dopamine agonists but is much milder. 

Side effects and problems of anticholinergics 

Another reason these drugs are not a first choice for treating Parkinson’s are their side effects. Some people may experience confusion, a dry mouth, constipation, and blurred vision when taking anticholinergics. 

Anticholinergics may interfere with levodopa absorption in the small bowel, which reduces the effectiveness of Madopar or Sinemet, forms of the drug levodopa. 

Anticholinergics are not usually prescribed to older people with Parkinson’s because there is an increased risk of memory loss and, in men, problems urinating. 

There is one glutamate antagonist, Amantadine, which can be prescribed to treat Parkinson’s symptoms. The generic name is amantadine, but it’s prescribed under the name Symmetrel. 

Exactly how this drug works for Parkinson’s isn’t fully understood yet. It may modify levels of certain chemicals in the brain. 

It’s most likely to be given along with other drug treatments for Parkinson’s and is available in capsules. 

The drug has only a mild effect, helps only a minority of people and its effectiveness may be short-lived. 

Amantadine may have a stimulatory effect and can help some people with tiredness, for this reason it should not be taken in the evening or before bed. It can be used to treat tremor and stiff muscles and can reduce unwanted involuntary movements without making other symptoms worse. 

Side effects of glutamate antagonists 

It’s not a first-choice treatment for Parkinson’s and has a limited effect. Side effects include: 

  • Blurred vision, fainting, confusion, or dizziness 
  • Interrupted sleep 
  • Swelling of the ankles or a mottled appearance on the skin of the lower leg. 

Parkinson’s medication general side effects

Taking Parkinson’s medication can cause side effects including:

Side-effects can usually be managed and it’s recommended to discuss your experiences and any concerns with your treating doctor.

Managing Parkinson’s medication

Each person with Parkinson’s has different medication needs and it can take time to find what works best.

Parkinson’s symptoms can have a greater impact on your life as the condition progresses and medication needs will change. There are many ways to record symptoms including keeping a diary of symptoms and when they occur. How best to record symptoms should be discussed with your GP or specialist. This information can be valuable in adjusting medications and timing. It’s important to avoid changing times or doses without talking to your treating doctor.

Some treatments for conditions other than Parkinson’s can cause problems for people taking Parkinson’s medication. It’s a good idea to keep an updated list of all medicines you’re taking including prescribed, over-the-counter, and supplements, to show to your treating doctor or a pharmacist before starting or stopping any medicines.

When going to hospital it’s essential that hospital staff understand that Parkinson’s medication is required to be administered at the specific time prescribed for the patient – not just at routine drug rounds. It’s advised that the admitting doctor record the prescribed dose and times on the patient’s drug chart.

Tips for visiting a doctor

  • Write a list of concerns or symptoms to discuss during your appointment.
  • Create an updated list of all your current medications.
  • Be honest about the symptoms you’re experiencing.
  • If you don’t understand something, ask your doctor to repeat it or explain it a different way.
  • Write down anything important or ask your doctor to write it down.
  • Bring a family member or other support person to your appointment.

If you speak a language other than English, it’s very important to have an interpreter present. You can ask for an interpreter when booking your appointment. Translation services for medical appointments are usually free of charge.

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Being diagnosed with Parkinson’s is a personal experience but no one has to face Parkinson’s alone. Support and information can make a significant and positive difference to the lives of those living with Parkinson’s, their families and carers.

Please note: Fight Parkinson’s uses the phrase Parkinson’s rather than Parkinson’s Disease to reflect the community’s preference. Parkinson’s Disease is used only when necessary such as in medical, research or government contents, or in direct quotes.