I have received an important pamphlet produced by Parkinson Society Canada. It lists the most common drugs administered to Parkinson’s patients today and a checklist for caregivers to periodically note the progression of the disease for the patient’s neurologist, who monitors and administers his/her medication. Some excerpts appear below. Bonnie
WHAT MEDICATIONS ARE USED TO TREAT PARKINSON’S SYMPTOMS?
Since many of the motor symptoms of Parkinson’s are the result of a lack of dopamine in the brain, most drugs used to treat Parkinson’s are aimed at temporarily replenishing or imitating dopamine. The following list is a guide to medications approved by Health Canada to treat symptoms of Parkinson’s. Speak to your doctor for detailed information regarding effectiveness and side effects of a particular drug.
Levodopa (levodopa/benserazide [Prolopa®], levodopa/carbidopa [Sinemet®, Sinemet® CR])
• Converted into dopamine in the brain and stored in nerve cells to replace depleted dopamine
• Combined with another drug, carbidopa or benzerazide, allows more levodopa to get to the brain and reduces side effects
• Helps improve muscle rigidity and movement
• Side effects include dyskinesias* (involuntary movements)
• Over years of use, may be associated with “wearing off”*
Dopamine Agonists (bromocriptine [Parlodel®], pramipexole [Mirapex®], ropinirole [ReQuip®])
• “Mimics” or imitates action of dopamine
• Can be used as initial treatment or with levodopa in advanced stages
• Side effects include sleepiness, hallucinations, leg swelling and obsessions with food, sex and activities such as shopping, gambling and Internet use
• Enhances dopamine release and blocks glutamate, a brain transmitter
• Used to treat early symptoms
• Can reduce dyskinesias and improve wearing off
COMT Inhibitors (entacapone [Comtan®])
• Block a key enzyme responsible for breaking down levodopa before it reaches the brain
• Can improve duration of response to levodopa
• Side effects include dyskinesias
• Substitutes individually administered immediate-release levodopa/carbidopa + entacapone
• Used to replace immediate-release levodopa/carbidopa (without entacapone) when patients experience end-of-dose wearing off
Levodopa/carbidopa intestinal gel (DuodopaTM)
• Levodopa/carbidopa gel administered throughout the day with a pump via a tube directly into the small intestine
• Used in advanced Parkinson’s disease
• Approved under the Notice of Compliance with Conditions (NOC/c) policy2
Monoamine-Oxidase-B Inhibitors (MAO-B) (selegiline [Eldepryal®], rasagiline [Azilect®])
• Enhance effect of dopamine by preventing its breakdown
• Side effects include dyskinesias
Anticholinergic Drugs (Apo®-trihex, benztropine [Cogentin®], trihexyphenidyl [Artane®])
• Corrects imbalance between dopamine and acetylcholine
Dyskinesias are involuntary, purposeless movements of any body part. They may be mild (slight ankle twisting) or severe (uncontrollable writhing movements). Dyskinesias are usually felt during the time you are on when you have taken your medication; this is also called “peak dose dyskinesias”.
When medications such as levodopa relieve symptoms, you are in your “on” state. This means you can do your daily activities. When the medication does not work and the symptoms return, you are in your “off” state. This means you may not be able to do the things you want or need to do. If your symptoms return before your next dose of medication, it means you are in a “wearing off” state.
SURGERY AND PARKINSON’S MEDICATIONS
If you are going to have surgery, especially requiring a general anaesthetic, talk to your surgeon/anaesthesist ahead of time. He/she may want to discuss anaesthesia, pain relief and your drug treatment with your doctor/neurologist. Certain pain relief drugs can interact with Parkinson’s medications.
How can I get the most benefit from my Parkinson’s medications?
What are the side effects of Parkinson’s drugs?
The most common reactions (which occur within the first several days of a new treatment) include nausea, vomiting, dizziness (drop in blood pressure), sleepiness and visual hallucinations.
In the last few years, levodopa and dopamine agonists in particular (ropinirole [ReQuip], pramipexole [Mirapex]) have been associated with the emergence of behavioral changes such as impulse control disorders. These are characterized by failure to resist an impulse to perform certain actions.
Impulse control disorders include a range of behaviors such as compulsive gambling (up to 5% of treated patients) or shopping, hypersexuality, binge eating, addiction to the Internet or to other recreational activities. These activities are often pleasant in the moment, but over time may become harmful to you or to others. If you are experiencing these behaviours, tell your neurologist/doctor. Often the medication can be adjusted which can reduce or control the behaviour.
Care partners can play an important role in helping to identify when these behaviours occur. If you are a care partner, tell the person if you have noticed a change in his/her behaviour or personality and encourage him/her to speak with the doctor immediately so medication can be adjusted.
What are non-motor symptoms?
People with Parkinson’s often experience non-motor symptoms which can be more bothersome than motor-symptoms. Some examples of non-motor symptoms include constipation, depression or anxiety, sleep disorders and cognitive changes. Adjusting the Parkinson’s medications can often control these symptoms. If this approach doesn’t work, specific treatment may be required. For example, depression is common in Parkinson’s and usually responds well to treatment. Medications to improve cognitive function are also available.
How will Parkinson’s symptoms change over time?
Parkinson’s will change over time. Often the changes are subtle and you may not notice them. The following checklist may help you identify these changes. Complete the checklist every 9 to 12 months. Discuss the changes with your doctor.
Source: Info Parkinson, Parkinson Society Quebec, Newsletter Spring 2009 and Summer 2009