Parkinson's disease (PD) is a progressive neurological disorder. Average age of onset is 60 years, but onset can occur as early as the third decade of life or at any point thereafter. It is estimated that over 1,000,000 people suffer from PD in the United States and an additional 50,000 to 60,000 new cases are diagnosed each year. This represents approximately 0.3% of the general population, 3% of persons over the age of 65 and 10% of persons over the age of 80. Although we know that the loss of dopamine in an area of the brain called the substantia nigra is related to the development of PD, the cause of PD is currently unknown.
Tremor at rest (arm or leg is not in use), slowness of movement (bradykinesia) and rigidity (stiffness) are the primary symptoms of PD, as well as difficulties with walking and balance (postural instability) as the disease progresses. PD generally starts on one side of the body. Initial symptoms often include one arm that does not swing, decreased facial expression (hypomania), small handwriting (micrographia), short shuffling walk and speech and swallowing changes. PD can also result in non-motor symptoms such as depression, anxiety, apathy, sleep disturbances, slowed thinking and in about 30% of patients, dementia in the later stages of the disease.
Treatment for PD is generally started when symptoms begin to affect the performance of daily activities. The particular treatment for each person is selected based on the persons age, disease characteristics and severity, and lifestyle. There are multiple treatment options available including the following:
- MAO-B inhibitors - blocks MAO-B in the brain to increase natural dopamine
- Rasagiline (Azilect) - once daily treatment used as initial therapy and in combination with levodopa in more advanced disease
- Selegiline (Eldepryl, generic selegiline) - generally taken twice daily; used as initial therapy and in combination with levodopa in more advanced disease
- Orally disintegrating selegiline (Zelapar) - once daily treatment used in patients on levodopa with wearing off (loss of symptom control towards end of dose)
- Dopamine agonists - simtulate post-synaptic dopamine receptors
- Pramipexole (Mirapex, generic) - generally taken 3 times daily, used as initial therapy and in combination with levodopa in more advanced disease
- Pramipexole extended release (Mirapex ER) - once daily formulation used as initial therapy or in combination with levodopa in more advanced disease
- Ropinirole immediate release (Requip, generic) generally taken 3 times daily; used as initial therapy an in combination with levodopa in more advanced disease
- Ropinirole 24-hour prolonged release (Requip XL) - once daily treatment used as initial therapy or in combination with levodopa in more advanced disease
- Rotigitine Transdermal System (Neupro) - once daily patch used as initial therapy or in combination with levodopa in advanced disease
- Apomorphine (Apokyn) - injectable treatment; used as a rescue therapy in advanced disease for severe off periods
- Carbidopa/levodopa (Sinemet, Sinemet CR, generic formulations, Parcopa)
- Most effective treatment for PD and can be used as initial treatment but generally used later in the disease to delay the development of motor complications (dyskinesia and on/off periods)
- COMT inhibitors - blocks COMT to increase the amount of levodopa that reaches the brain; used only with levodopa
- Amantadine (Symmetrel, generic)
- occasionally used in early disease with mild symptoms; more commonly used in more advanced disease to control dyskinesia
- Anticholinergics - block acetylcholine; minimal benefit; can help drooling
- Deep Brain Stimulation (see surgical treatment)
- Surgical treatment option for persons who respond well to levodopa but have motor fluctuations (on/off periods) and dyskinesia that cannot be adequately controlled with medications
See related resources for more information about Parkinson's disease.