What Should I Know about Parkinson’s Medications?

Levodopa that is taken in a pill moves from the digestive tract to the brain, converting to dopamine in the brain.

Dopamine itself cannot cross blood-brain barrier, but levodopa can. After the conversion to dopamine, levodopa is used to boost dopamine levels depleted by the Parkinson’s disease process.

When this treatment was first discovered in the 1950s, levodopa was given to people on its own, and large doses were needed. These large doses caused severe side effects like nausea, so carbidopa was added.

Carbidopa improved the effect of levodopa. This allowed people who used levodopa to use 80 percent less of the medication to achieve the same results.

Today, carbidopa-levodopa remains a first-line treatment for Parkinson’s disease and is available in extended- and controlled-release forms.

Administration

Carbidopa-levodopa is available as a pill or liquid that’s taken orally. Formulations vary by manufacturer, with available options including:

• Sinemet: 10mg/100mg, 25mg/100 mg, 25mg/250mg oral tablet
• Parcopa: 10mg/100mg, 25mg/100mg, 25mg/250mg oral tablet
• Sinemet controlled release (CR): 25mg/100mg, 50mg/200mg oral tablet
• Rytary extended release (ER): 23.75mg/95mg, 36.25mg/145mg, 48.75mg/195mg, 61.25mg/245mg oral tablet
• Duopa extended release (ER): 4.63mg/20mg liquid suspension

These medications are taken several times per day depending on the formulation. Traditional Sinemet is taken every 6 to 8 hours.

Dose changes must be done gradually by your doctor.

Benefits

Carbidopa-levodopa medications help replace depleted dopamine levels to control Parkinson’s symptoms.

This medication can help lessen symptoms like slowness, tremors, and movement problems, but it is not likely to cure them completely.

How long does it take to work?

Traditional Sinemet takes about 30 minutes to reach its peak effect, while extended- or controlled-release formulas take about 2 hours.

Side effects

• abnormal, uncoordinated movements (dyskinesia)
• nausea
• abdominal pain
• confusion
• dizziness
• heart rate or blood pressure changes

Efficacy

Since no carbidopa-levodopa formulations offer constant dosing, people who take this medication will have “on” and “off” times where symptoms become better and worse.

Levodopa is not effective on some symptoms of Parkinson’s that affect balance, speech, or swallowing. Dosages usually need to be increased over time as the disease progresses.

Dopamine agonists are another medication group that helps make up for the lack of dopamine in people with Parkinson’s disease.

While these medications do notconvert to dopamine in the brain, they have the same effect.

Administration

• Pramipexole (Mirapex): 0.125-mg, 0.25-mg, 0.5-mg, 0.75-mg, 1-mg, or 1.5-mg oral tablets three times per day, or 0.375-mg, 0.75-mg., 1.5-mg, 2.25-mg, 3-mg, 3.75-mg, or 4.5-mg oral extended-release tablets once per day
• Ropinirole (Requip): 0.25-mg, 0.5-mg, 1-mg, 2-mg, 3-mg, 4-mg, or 5-mg oral tablets three times per day, or 2-mg, 4-mg, 6-mg, 8-mg, or 12-mg extended-release tablets once per day
• Apomorphine (Apokyn): 30-mg/3-ml vial for injection, 0.2 mg per dose
• Apomorphine (Kynmobi): sublingual film, 10 mg, 15 mg, 20 mg, 25 mg, and 30 mg
• Rotigotine (Neupro): 1-mg, 2-mg, 3-mg, 4-mg, 6-mg, or 8-mg transdermal patches, 4 mg–8 mg max per day

Benefits

Dopamine agonists can improve the motor symptoms that come with Parkinson’s disease but are not as effective as levodopa.

Typically used early in the disease process, dopamine agonists may be combined with carbidopa-levodopa as the disease progresses. These medications help most with stiffness and tremors.

How long does it take to work?

Injectable dopamine agonists like apomorphine work as quickly as 10 minutes.

Oral medications reach their peak effectiveness in about 2 hours.

Side effects

• drowsiness
• hallucinations
• leg swelling or discoloration
• compulsive behaviors
• dyskinesia

Efficacy

These are the most frequently used medications to treat Parkinson’s disease after carbidopa-levidopa.

They can also be combined with carbidopa-levidopa in later stages of the disease to aid in movement and tremor control.

Monoamine oxidase Type B (MAO-B) is an enzyme that breaks down dopamine in the brain. By blocking this enzyme, MAO-B inhibitors leave more dopamine for the body to use.

Administration

• Selegiline (I-deprenyl, Eldepryl): 5-mg oral tablet taken twice per day
• Selegiline HCL (Zelapar): 1.25-mg and 2.5-mg orally disintegrating tablet taken once daily
• Rasagiline (Azilect): 0.5-mg and 1-mg oral tablet taken once per day
• Safinamide (Xadago): 500-mg and 100-mg oral tablet taken once per day

Benefits

This medication reduces the amount of dopamine that is broken down in the brain and can also help with some motor symptoms.

How long does it take to work?

These medications take time to build up in your system before they begin to have the full effect.

It can take weeks before you notice any changes.

Side effects

• nausea
• dry mouth
• constipation
• dizziness
• confusion
• hallucinations

Efficacy

While MAO-B inhibitors can help Parkinson’s symptoms, they are not usually used as a primary treatment.

Instead, they are an adjunctive (or add-on) therapy used alongside other medications.

COMT inhibitors help prevent an enzyme called catechol-O-methyl transferase (COMT) from deactivating levodopa before it has a chance to be absorbed into the bloodstream.

Administration

• Entacapone (Comtan): 200-mg oral tablet taken four to eight times per day with levodopa doses
• Tolcapone (Tasmar): 100-mg or 200-mg oral tablets taken one to three times per day
• Carbidopa/levodopa/entacapone tablets (Stalevo): 12.5/50/200-mg, 18.75/75/200-mg, 25/100/200-mg, 31.25/125/200-mg, 37.5/150/200-mg, or 50/200/200-mg oral tablets taken multiple times daily
• Opicapone (Ongentys): 25-mg and 50-mg oral capsules taken once daily

Benefits

This medication is used alongside levodopa to treat motor fluctuations and “off” time.

How long does it take to work?

This medication reaches its peak in about 1 hour.

Side effects

• dyskinesia
• confusion
• hallucinations
• urine discoloration
• diarrhea

Efficacy

This medication is only effective when taken alongside levodopa.

Originally developed as an antiviral treatment, amantadine was accidentally discovered to reduce tremors.

Its exact function is not fully understood, but it’s believed to act on a number of receptors in the brain.

Administration

• Amantadine (Symmetrel): 100-mg capsules, 100-mg tablets, 50-mg/5-ml syrup taken two to three times per day
• Amantadine ER capsules (Gocovri): 68.5-mg and 137-mg capsules taken once per day at bedtime
• Amantadine ER tablets (Osmolex ER): 129-mg, 193-mg, and 258-mg tablets taken once per day in the morning

Benefits

Amantadine can reduce tremors and other movement problems.

How long does it take to work?

Amantadine takes about 48 hours to begin taking full effect from the time the medication is started.

Side effects

• dizziness
• hallucinations
• low blood pressure
• nausea
• insomnia
• confusion
• paranoia
• leg discoloration

Efficacy

This medication can be helpful alone or taken with other medications like levodopa to decrease muscle problems and tremors from Parkinson’s.

Anticholinergics decrease the power of acetylcholine, a neurotransmitter that helps regulate movement.

This medication can also help reduce abnormal contractions and oral secretions.

Administration

• Benzotropine (Cogentin): 0.5-mg, 1-mg, 2-mg oral tablets taken two to three times daily
• Trihexyphenidyl HCL: 2-mg or 5-mg tablets, or a 2-mg/5-ml liquid taken two to three times daily

Benefits

Anticholinergics can help reduce involuntary muscle contractions and tremors.

How long does it take to work?

These medications begin working immediately.

Side effects

• confusion
• hallucinations
• decreased memory
• dry mouth
• blurry vision
• urinary retention

Efficacy

Anticholinergics have the greatest benefit in younger patients whose primary symptom is tremors.

Adenosine A2a antagonists manipulate the receptor in the brain that is responsible for slowed movement in Parkinson’s disease. While the exact way the adenosine A2a antagonists work is unknown, when combined with Levadopa they can improve motor function.

This medication can also increase the sensitivity of dopamine receptors to help reduce motor symptoms in Parkinson’s.

Administration

• Istradefylline (Nourianz): 20-mg or 40-mg oral tablets taken once per day

Benefits

This medication reduces motor symptoms of Parkinson’s when used with other medications.

How long does it take to work?

This medication reaches its peak time in about 4 hours, but it requires several weeks to achieve lasting effects.

Side effects

• dyskinesia
• insomnia
• dizziness
• hallucinations

Efficacy

These medications work well in combination with other Parkinson’s treatments, but people who smoke 20 cigarettes or more per day will require larger doses.

There is currently no known cure for Parkinson’s disease, and treatment focuses on relieving the symptoms caused by the disease.

Numerous research studies are underway investigating both curative therapies as well as new strategies to manage Parkinson’s symptoms.

There are numerous studies investigating new treatments for Parkinson’s disease.

There has been new information about the role of autoimmunity and T-cells in the development of Parkinson’s disease, possibly opening the door to a role for biologics.

Stem cells are also being investigated as a treatment option for Parkinson’s disease.

Parkinson’s disease can cause a host of movement problems, including stiffness, tremors, and balance issues.

You may want to seek treatment early to increase your quality of life, but you should certainly see a doctor when safety becomes a concern due to falls or severe movement problems.

Parkinson’s disease is a progressive neurological disorder that currently has no definitive cure. Treatments focus on relieving the symptoms of the disease, which usually involve movement, coordination, and balance problems.

There is no one medication to treat Parkinson’s. Work closely with a doctor to find the right combination of therapies for your symptoms.