Researchers have yet to discover a cure for Parkinson's disease, but treatments have come a long way in recent years. Today, several different medications and other therapies are available to control symptoms like tremors and stiffness.
It's important for your loved one to take their medication exactly as the doctor prescribed. You can also offer support and gentle reminders.
To be helpful, you need to know which medications treat Parkinson's disease, and how they work.
Dopamine medications
People with Parkinson's have a lack of dopamine, which is a brain chemical that helps to keep movements smooth. This is why people with the condition walk slowly and have rigid muscles. The main drugs used to treat Parkinson's work by increasing the amount of dopamine in the brain.
Carbidopa-levodopa
A drug called levodopa, or L-DOPA, has been the main treatment for Parkinson's disease since the late 1960s. It continues to be the most effective drug because it replaces missing dopamine in the brain.
Most people with Parkinson's disease will take levodopa some time during the course of their treatment. Levodopa is converted into dopamine in the brain.
Many medications combine levodopa with carbidopa. Carbidopa prevents levodopa from breaking down in the gut or other parts of the body and converts it to dopamine before it reaches the brain. Adding carbidopa also helps prevent side effects like nausea and vomiting.
Carbidopa-levodopa comes in a few different forms:
- tablet (Parcopa, Sinemet)
- tablet that releases slowly so its effects last longer (Rytary, Sinemet CR)
- infusion that's delivered into the intestine through a tube (Duopa)
- inhaled powder (Inbrija)
Side effects from these drugs include:
- nausea
- dizziness
- dizziness when standing up (orthostatic hypotension)
- anxiety
- tics or other unusual muscle movements (dyskinesia)
- confusion
- seeing or hearing things that aren't real (hallucinations)
- sleepiness
Dopamine agonists
These drugs don't convert into dopamine in the brain. Instead, they act like dopamine. Some people take dopamine agonists together with levodopa to prevent their symptoms from returning during periods when levodopa wears off.
Dopamine agonists include:
- pramipexole (Mirapex, Mirapex ER), tablet and extended-release tablet
- ropinirole (Requip, Requip XL), tablet and extended-release tablet
- apomorphine (Apokyn), short-acting injection
- rotigotine (Neupro), patch
These medications cause some of the same side effects as carbidopa-levodopa, including nausea, dizziness, and sleepiness. They can also cause compulsive behaviors, such as gambling and overeating.
MAO B inhibitors
This group of drugs works differently than levodopa to increase dopamine levels in the brain. They block an enzyme that breaks down dopamine, which lengthens the effects of dopamine in the body.
MAO B inhibitors include:
- selegiline (Zelapar)
- rasagiline (Azilect)
- safinamide (Xadago)
These drugs can cause side effects such as:
- trouble sleeping (insomnia)
- dizziness
- nausea
- constipation
- stomach upset
- unusual movements (dyskinesia)
- hallucinations
- confusion
- headache
MAO B inhibitors may interact with certain:
- foods
- over-the-counter medications
- prescription medications
- supplements
Make sure you talk to your doctor about all medications and supplements your loved one takes.
COMT inhibitors
The drugs entacopine (Comtan) and tolcapone (Tasmar) also block an enzyme that breaks down dopamine in the brain. Stalevo is a combination drug that includes both carbidopa-levodopa and a COMT inhibitor.
COMT inhibitors cause many of the same side effects as carbidopa-levodopa. They can also damage the liver.
Other Parkinson's drugs
Although drugs that increase dopamine levels are the staples of Parkinson's treatment, a few other medications also help control symptoms.
Anticholinergics
Trihexyphenidyl (Artane) and benztropine (Cogentin) reduce tremors from Parkinson's disease. Their side effects include:
- dry eyes and mouth
- constipation
- trouble releasing urine
- memory problems
- depression
- hallucinations
Amantadine
This drug may help people with early-stage Parkinson's disease who have only mild symptoms. It can also be combined with carbidopa-levodopa treatment in the later stages of the disease.
Side effects include:
- leg swelling
- dizziness
- spots on the skin
- confusion
- dry eyes and mouth
- constipation
- sleepiness
Sticking to the treatment schedule
Early treatment for Parkinson's disease follows a pretty easy routine. Your loved one will take carbidopa- levodopa a few times a day on a set schedule.
After a few years on treatment, brain cells lose their ability to store dopamine and become more sensitive to the drug. This may cause the first dose of medication to stop working before it's time for the next dose, which is called 'wearing off.'
When this happens, your loved one's doctor will work with them to adjust the medication dose or add another drug to prevent 'off' periods. It can take some time and patience to get the drug type and dose just right.
People with Parkinson's disease who have been taking levodopa for a number of years can also develop dyskinesia, which causes involuntary movements. Doctors can adjust medications to reduce dyskinesia.
Timing is critical when it comes to taking Parkinson's medications. To control symptoms, your loved one must take their medication in the right dose and at the right time each day. You can help during medication changes by reminding them to take their pill on the new schedule, or by buying them an automated pill dispenser to make dosing easier.
What happens when Parkinson's medications stop working
Today, doctors have many different medications to control Parkinson's symptoms. It's likely your loved one will find one drug — or a combination of drugs — that works.
Other types of treatments are also available, including deep brain stimulation (DBS). In this treatment, a wire called a lead is surgically placed into a part of the brain that controls movement. The wire is attached to a pacemaker-like device called an impulse generator that's implanted under the collarbone. The device sends electrical pulses to stimulate the brain and stop the abnormal brain impulses that cause Parkinson's symptoms.
Takeaway
Parkinson's treatments are very good at controlling symptoms. The drug types and doses your loved one takes may need to be adjusted over the years. You can help with this process by learning about the available medications, and by offering support to help your loved one stick to his or her treatment routine.