As Parkinson's disease is a chronic disorder, Treatment of Parkinson's Disease requires broad-based management including patient and family education, support group services, general wellness maintenance, exercise, and nutrition. At present, there is no cure for PD, but medications or surgery can provide relief from the symptoms.

While many medications treat Parkinson's, none actually reverse the effects of the disease or cure it. People with Parkinson's therefore often must take a variety of medications to manage the disease's symptoms.[1] The Parkinson's Disease Foundation (PDF) has a chart on its website that provides details about Parkinson's medications.

Several medications currently in development seek to better address motor fluctuations and nonmotor symptoms of Parkinson's Disease. However, none are yet on the market with specific approval to treat Parkinson's.

Levodopa

The most widely used form of treatment is L-dopa in various forms. L-dopa is transformed into dopamine in the dopaminergic neurons by L-aromatic amino acid decarboxylase (often known by its former name dopa-decarboxylase). However, only 1-5% of L-DOPA enters the dopaminergic neurons. The remaining L-DOPA is often metabolised to dopamine elsewhere, causing a wide variety of side effects. Due to feedback inhibition, L-dopa results in a reduction in the endogenous formation of L-dopa, and so eventually becomes counterproductive.

Carbidopa and Benserazide are dopa decarboxylase inhibitors. They help to prevent the metabolism of L-dopa before it reaches the dopaminergic neurons and are general given as combination preparations of carbidopa/levodopa (co-careldopa BAN) co-careldopa combined L-dopa and carbidopa in fixed ratios in such branded products of Sinemet and Parcopa and Benserazide/levodopa (co-beneldopa BAN) as Madopar. There are also controlled release versions of Sinemet and Madopar that spread out the effect of the L-dopa. Duodopa is a combination of levodopa and carbidopa, dispersed as a viscous gel. Using a patient-operated portable pump, the drug is continuously delivered via a tube directly into the upper small intestine, where it is rapidly absorbed.

Talcopone inhibits the COMT enzyme, thereby prolonging the effects of L-dopa, and so has been used to complement L-dopa. However, due to its side effects, such as possible liver failure is limited in its availability. A similar drug, entacapone, has similar efficacy and has not been shown to cause significant alterations of liver function. Stalevo[3] contains Levodopa, Carbidopa and Entacapone.

Mucuna pruriens, is a natural source of therapeutic quantities of L-dopa.
Dopamine agonists

The dopamine-agonists bromocriptine (Parlodel), pergolide (Permax), pramipexole (Mirapex), ropinirole (Requip), cabergoline (Cabaser), apomorphine (Apokyn), and lisuride (Revanil), are moderately effective. These have their own side effects including those listed above in addition to somnolence, hallucinations and /or insomnia. Dopamine agonists initially act by stimulating some of the dopamine receptors. However, they cause the dopamine receptors to become progressively less sensitive, thereby eventually increasing the symptoms.
[edit] MAO-B inhibitors

Selegiline (Eldepryl) and rasagiline (Azilect) reduce the symptoms by inhibiting monoamine oxidase-B (MAO-B), which inhibits the breakdown of dopamine secreted by the dopaminergic neurons. By-products of selegiline include amphetamine and methamphetamine, which can cause side effects such as insomnia. Use of L-dopa in conjunction with selegiline has increased mortality rates that have not been effectively explained. Another side effect of the combination can be stomatitis. One report raised concern about increased mortality when MAO-B inhibitors were combined with L-dopa [4]; however subsequent studies have not confirmed this finding[5]. Unlike other non selective monoamine oxidase inhibitors, tyramine-containing foods do not cause a hypertensive crisis.

for more, visit http://en.wikipedia.org/wiki/Treatments_of_Parkinson%27s_Disease