Medications may help you manage problems with walking, movement and tremor. These medications increase or substitute for dopamine.
People with Parkinson’s disease have low brain dopamine concentrations. However, dopamine can’t be given directly, as it can’t enter your brain.
You may have significant improvement of your symptoms after beginning Parkinson’s disease treatment. Over time, however, the benefits of drugs frequently diminish or become less consistent. You can usually still control your symptoms fairly well.
Medications your doctor may prescribe include:
Carbidopa-levodopa. Levodopa, the most effective Parkinson’s disease medication, is a natural chemical that passes into your brain and is converted to dopamine.
Levodopa is combined with carbidopa (Lodosyn), which protects levodopa from early conversion to dopamine outside your brain. This prevents or lessens side effects such as nausea.
Side effects may include nausea or lightheadedness (orthostatic hypotension).
After years, as your disease progresses, the benefit from levodopa may become less stable, with a tendency to wax and wane (“wearing off”).
Also, you may experience involuntary movements (dyskinesia) after taking higher doses of levodopa. Your doctor may lessen your dose or adjust the times of your doses to control these effects.
Carbidopa-levodopa infusion. Duopa is a brand-name medication made up of carbidopa and levodopa. However, it’s administered through a feeding tube that delivers the medication in a gel form directly to the small intestine.
Duopa is for patients with more-advanced Parkinson’s who still respond to carbidopa-levodopa, but who have a lot of fluctuations in their response. Because Duopa is continually infused, blood levels of the two drugs remain constant.
Placement of the tube requires a small surgical procedure. Risks associated with having the tube include the tube falling out or infections at the infusion site.
Dopamine agonists. Unlike levodopa, dopamine agonists don’t change into dopamine. Instead, they mimic dopamine effects in your brain.
They aren’t as effective as levodopa in treating your symptoms. However, they last longer and may be used with levodopa to smooth the sometimes off-and-on effect of levodopa.
Dopamine agonists include pramipexole (Mirapex), ropinirole (Requip) and rotigotine (Neupro, given as a patch). Apomorphine (Apokyn), is a short-acting injectable dopamine agonist used for quick relief.
Some of the side effects of dopamine agonists are similar to the side effects of carbidopa-levodopa. But they can also include hallucinations, sleepiness and compulsive behaviors such as hypersexuality, gambling and eating. If you’re taking these medications and you behave in a way that’s out of character for you, talk to your doctor.
MAO B inhibitors. These medications include selegiline (Eldepryl, Zelapar), rasagiline (Azilect) and safinamide (Xadago). They help prevent the breakdown of brain dopamine by inhibiting the brain enzyme monoamine oxidase B (MAO B). This enzyme metabolizes brain dopamine. Side effects may include nausea or insomnia.
When added to carbidopa-levodopa, these medications increase the risk of hallucinations.
These medications are not often used in combination with most antidepressants or certain narcotics due to potentially serious but rare reactions. Check with your doctor before taking any additional medications with an MAO B inhibitor.
Catechol O-methyltransferase (COMT) inhibitors. Entacapone (Comtan) is the primary medication from this class. This medication mildly prolongs the effect of levodopa therapy by blocking an enzyme that breaks down dopamine.
Side effects, including an increased risk of involuntary movements (dyskinesia), mainly result from an enhanced levodopa effect. Other side effects include diarrhea or other enhanced levodopa side effects.
Tolcapone (Tasmar) is another COMT inhibitor that is rarely prescribed due to a risk of serious liver damage and liver failure.
Anticholinergics. These medications were used for many years to help control the tremor associated with Parkinson’s disease. Several anticholinergic medications are available, including benztropine (Cogentin) or trihexyphenidyl.
However, their modest benefits are often offset by side effects such as impaired memory, confusion, hallucinations, constipation, dry mouth and impaired urination.
Amantadine. Doctors may prescribe amantadine alone to provide short-term relief of symptoms of mild, early-stage Parkinson’s disease. It may also be given with carbidopa-levodopa therapy during the later stages of Parkinson’s disease to control involuntary movements (dyskinesia) induced by carbidopa-levodopa.
Side effects may include a purple mottling of the skin, ankle swelling or hallucinations.