Parkinson's Disease Medications
Although there is no medication currently available that can cure or slow down the progression of Parkinson's disease, several drugs are available that can help relieve symptoms of this condition. Levodopa is the most common medicine used for treating Parkinson's disease. Other medications include dopamine agonists, MAOIs, and anticholinergics.
A variety of medications can provide dramatic relief from Parkinson's disease symptoms. However, any medications that are used to treat this condition lose their benefit or begin to cause intolerable side effects over time. Also, no medication is available that can stop or slow down the progression of the disease.
Parkinson's disease medications can be separated into different classes based on the way they work. These different classes of Parkinson's drugs include:
- Dopamine agonists
- Monoamine oxidase inhibitors (MAOIs)
- Other miscellaneous medications.
There may be several medications approved for treating Parkinson's disease within each of these classes.
Levodopa as a Parkinson's Disease Medication
The most commonly used medications for Parkinson's disease include those that work directly or indirectly to increase the level of dopamine in the brain. Dopamine is a chemical messenger (neurotransmitter) in the brain. However, people cannot simply take dopamine, because it does not easily pass through blood vessels into the brain.
Instead, people must take medications that mimic the effects of dopamine (known as dopamine agonists) or that are dopamine precursors (substances such as levodopa that cross the blood-brain barrier and are then changed into dopamine).
The "gold standard" and most frequently prescribed medication for Parkinson's disease is levodopa.
First introduced in the 1960s, levodopa delays the onset of debilitating symptoms and allows the majority of people with Parkinson's disease -- who would otherwise be quite disabled -- to extend the period of time in which they can lead relatively normal, productive lives.
For Parkinson's disease treatment, people are usually given levodopa combined with carbidopa (Sinemet®, Sinemet® CR, or Parcopa®). When added to levodopa, carbidopa delays the conversion of levodopa into dopamine until it reaches the brain, thereby preventing or diminishing some of the side effects that often accompany levodopa therapy. Carbidopa also reduces the amount of levodopa needed.
Although levodopa helps at least three-quarters of people with the disease, not all symptoms respond equally to this Parkinson's disease drug. Bradykinesia (slow movement) and rigidity respond best to this medication, while tremors may be only marginally reduced. Problems with balance and other symptoms may not improve at all.
Also, people who have taken other Parkinson's medications before starting levodopa therapy may have to cut back or eliminate these drugs in order to experience the full benefit of levodopa. Once levodopa therapy starts, people often respond dramatically. However, people taking levodopa may need to gradually increase the dose for maximum benefit.
Because a high-protein diet can interfere with the absorption of levodopa, some healthcare providers recommend that people who are taking the drug only consume protein during their evening meal.
Levodopa is so effective that some people may forget they have Parkinson's. But levodopa is not a cure. Although it can diminish the symptoms of Parkinson's disease, it does not replace lost nerve cells, and it does not stop the progression of the disease.