The information provided here is meant to give you a general idea about each of the medications listed below. Only the most general side effects are included, so ask your doctor if you need to take any special precautions. Use each of these medications only as recommended by your doctor and according to the instructions provided. If you have further questions about usage or side effects, contact your doctor.

Medications for Parkinson’s disease work in a variety of different ways. The primary strategy is to increase the amount of dopamine, as it is this neurotransmitter that is decreased in patients with Parkinson’s disease. Although most patients respond to medications initially, the effects may wear off over time as the disease progresses. When a particular medication stops working, you may have to increase the dose, switch medications, stop and then restart a medication, or add on another medication. In addition, many people experience disabling side effects (specifically, rapid “wearing-off” of the drug and abnormal movements, called dyskinesias) from long-term dopamine-replacement therapy, which requires a decrease in dose and possible substitution of another medication or other form of therapy.

Prescription Medications

Levodopa alone or in combination with carbidopa or entacapone

  • Carbidopa/levodopa (Sinemet)
  • Carbidopa/levodopa controlled-release (Sinemet CR)
  • Carbidopa/levodopa/entacapone (Stalevo)

Dopamine agonists

  • Bromocriptine (Parlodel)
  • Cabergoline (Dostinex)
  • Pramipexole (Mirapex)
  • Ropinirole (Requip)
  • Apomorphine injection (Apoken)

Monoamine oxidase type B inhibitor

  • Selegiline (Eldepryl)

COMT inhibitors

  • Tolcapone (Tasmar)
  • Entacapone (Comtan)

Anticholinergics

  • Trihexyphenidyl (Artane)
  • Benztropine (Cogentin)

Glutamate antagonist and dopamine releaser

  • Amantadine (Symmetrel)

Prescription Medications

Levodopa

Levodopa is the most effective treatment for symptoms. It is a precursor to dopamine and converted to dopamine once transported into the brain.

Common names include:

  • Dopar
  • Larodopa

Levodopa and Carbidopa

Common names include:

  • Carbidopa/levodopa (Sinemet)
  • Carbidopa/levodopa controlled-release (Sinemet CR)
  • Carbidopa/levodopa/entacapone (Stalevo)

Levodopa helps increase the amount of dopamine within the brain. This can help improve symptoms of Parkinson’s disease, particularly rigidity and slowness. Unfortunately, the body metabolizes (breaks down) this drug very quickly, so you’ll have to take another dose every 90 minutes or so. As a result, you’ll often be given a medication that combines levodopa with carbidopa, a substance that slows the breakdown of levodopa. You’ll only have to take this medication every 4-6 hours.

If you’re taking levodopa alone, don’t take vitamin B6 supplements without your doctor’s knowledge since they can speed up the breakdown of levodopa. Because bananas, egg yolks, lima beans, meats, peanuts, and whole grain cereals all contain large amounts of vitamin B6, ask your doctor how much of these food items you should eat on a daily basis.

Some people notice less effect from levodopa and levodopa/carbidopa combinations over time. The drugs may seem less effective, or their benefits may stop even before it’s time for the next dose. If this happens, talk to your doctor about increasing the dosage or increasing how frequently you take the medicine.

Don’t ever suddenly discontinue using these medications, unless your doctor advises it.

Possible side effects include:

  • Nausea
  • Vomiting
  • Dizziness
  • Dry mouth
  • Nightmares
  • Nervousness
  • Anxiety
  • Decreased appetite
  • Increased intestinal gas
  • Low blood pressure
  • Palpitations
  • Confusion
  • Agitation
  • Psychosis, paranoia, mania
  • Hallucinations, delusions
  • Nightmares, vivid dreams, night terrors

Stalevo was recently approved, and it adds entacapone, a COMT inhibitor (see below), to the levodopa/carbidopa combination. Side effects are reported to be those described above, plus those listed below for entacapone (Comtan).

Dopamine Agonists

Common names include:

These drugs affect the brain in a way similar to dopamine. They may be given by themselves early in Parkinson’s disease, or along with other medications (like levodopa) later in the course of the disease. Dopamine agonists cause less motor fluctuations and dyskinesias due to the longer duration of action.

Some people develop hallucinations or confusion while taking dopamine agonists and have to stop taking the medication. Don’t use alcohol while you’re taking a dopamine agonist. You’ll have unpleasant and potentially dangerous symptoms, including nausea, vomiting, fast heart rate, blurry vision, chest pain, headache, and extreme weakness.

Possible side effects include:

  • Dizziness
  • Drowsiness
  • Dry mouth
  • Nausea, vomiting
  • constipation
  • Headache
  • Ankle edema
  • Sudden low blood pressure when you first stand up (which can result in falling)
  • Sudden sleep attacks (These attacks can be very dangerous if they occur while you’re driving.)
  • Hallucinations, delusions
  • Compulsive gambling

Apomorphine (Apokyn) is a short acting dopamine agonist given as an injection in advanced cases. The medication was approved by the FDA for wearing-off spells. These spells occur in patients who have been receiving long-term dopamine replacement therapy. The side effects are similar to that of the dopamine agonists. But, nausea and vomiting have been reported to occur more often.

Note:Pergolide (Permax) was withdrawn from the market in March 2007 due to the risk of serious heart valve damage; cabergoline (Dostinex) has also been associated with a similar risk. The dopamine agonist bromocriptine is defined chemically as an “ergot-derivative” and has rare, but significant, side effects. Bromocriptine has been associated with rare reports of pericardial, pleural, and pulmonary fibrosis (thickening and scarring of the tissue lining the heart and lungs.) Talk to your doctor if you have been taking these medications and are concerned about potential side effects.

Monoamine Oxidase Type B Inhibitor

Common brand names include:

Selegiline is usually given along with levodopa or levodopa/carbidopa combinations. It interferes with the breakdown of dopamine in the brain.

You may have a severe reaction if you take this medicine along with the narcotic painkiller, meperidine (Demerol).

If you are taking selegiline at higher-than-usual doses, you may have a sudden, dangerous spike in blood pressure if you eat or drink things that contain a substance called tyramine. Tyramine is found in:

  • Aged cheeses
  • Beer, wine, and other alcoholic beverages
  • Smoked or pickled meats, chicken, fish, and cheeses
  • Caffeinated foods and beverages (colas, coffee, tea, chocolate)
  • Nonprescription medicines for colds, allergies, sinuses, cough, asthma, hay fever, and appetite control

Call your doctor right away if you notice:

  • Severe headache
  • Stiff neck
  • Chest pain
  • Abnormally fast or slow heartbeat
  • Severe nausea and vomiting
  • Increased sweating

Possible side effects include:

  • Dry mouth
  • Dizziness
  • Sudden low blood pressure when you first stand up (which can lead to falls)
  • Difficulty sleeping
  • Nausea, vomiting (mild)
  • Visual hallucinations
  • Agitation

COMT Inhibitors

Common names include:

COMT inhibitors are taken with levodopa preparations. They help decrease the rate of breakdown of levodopa, so more is available to work in the brain.

These medications can cause severe liver problems, so your doctor will probably run regular tests to monitor your liver function.

Possible side effects include:

  • Brownish-orange urine
  • Moderate to severe diarrhea
  • Dizziness, lightheadedness
  • Hallucinations and confusion (especially in the elderly)
  • Headaches
  • Somnolence

Anticholinergics

Common names include:

  • Trihexyphenidyl (Artane)
  • Benztropine (Cogentin)

These medications can decrease tremor and stiffness and improve muscle control.

You’ll have less chance of stomach irritation if you take these medications with food. Don’t take an anticholinergic medicine within the hour after you’ve taken medicine for diarrhea; the diarrhea medicine will interfere with the actions of the anticholinergic medicine. Don’t use alcohol while you're taking anticholinergic medicines. Check with your doctor before using any medications that make you drowsy.

Before you begin treatment with anticholinergic medicines, get your eyes checked by an ophthalmologist.

Possible side effects include:

  • Drowsiness
  • Dizziness
  • Sensitivity to bright lights
  • Dry mouth
  • Urinary retention
  • Blurred vision
  • Constipation
  • Fast heartbeat, palpitations
  • Mood changes
  • Memory difficulties
  • Confusion
  • Hallucinations

Amantadine

Common brand name:

Amantadine can help reduce stiffness and tremor and improve muscle control. Sometimes this medication stops working after you’ve been taking it for a while. Your doctor may recommend that you take a break (a “drug holiday”) from the medicine and then restart it. This may help the drug regain its effectiveness.

Don’t drink alcohol while you’re using amantadine. If you begin to feel depressed or suicidal, talk with your doctor right away.

Possible side effects include:

  • Dizziness, especially when first rising (which may increase risk of falls)
  • Confusion
  • Blurry vision
  • Difficulty concentrating
  • Dry mouth
  • Purplish-red blotchy skin rash
  • Depression
  • Nightmares
  • Insomnia
  • Hallucinations
  • Urinary retention
  • Lower extremity edema

Researchers are focusing on neuroprotective medications. These medications may be able treat the underlying problems causing Parkinson’s, not just the symptoms.

Special Considerations

If you are taking medications, follow these general guidelines:

  • Take your medication as directed. Do not change the amount or the schedule.
  • Do not stop taking them without talking to your doctor.
  • Do not share them.
  • Know what the results and side effects. Report them to your doctor.
  • Some drugs can be dangerous when mixed. Talk to a doctor or pharmacist if you are taking more than one drug. This includes over-the-counter medication and herb or dietary supplements.
  • Plan ahead for refills so you don’t run out.

When to Contact Your Doctor

  • The drug does not seem to be working.
  • You have undesired side effects.
  • You begin to have stomach problems while taking the medication.