Different ways to treat PD

There are several ways to manage Parkinson’s disease (PD). They include non-drug treatments, such as physical therapy, occupational therapy and dietary management; surgery such as a pallidotomy (removal of a part of the brain called the globus pallidus), thalamotomy (removal of part of the thalamus), or deep brain stimulation; and drug, or pharmacological, treatment. At present, there is no cure for Parkinson’s disease. Management of Parkinson’s disease relieves symptoms but does not cure it.

Drug therapies for PD

There are many drugs that can be effective for Parkinson’s disease, although effectiveness differs for every patient, depending on the stage of the disease, how long the drug has been used, and other factors. Side effects may prevent doctors from recommending the most effective dose, or they may require a new drug to counteract them.

Six categories of drugs are currently used to treat PD:

1. Dopamine replacers.

Levodopa, a dopamine replacer, is converted into dopamine by the brain. Dopamine is the neurotransmitter that is in short supply in PD patients. It is the single most effective treatment for the symptoms of PD. It may be started when symptoms begin, or when they become serious enough to interfere with work or daily living.

Levodopa usually remains effective for five years or longer, after which time some patients develop motor fluctuations, including peak-dose "dyskinesias" (abnormal movements such as tics, twisting, jerking of the limbs or restlessness), rapid loss of response after taking medication (known as the "ON–OFF" phenomenon), and unpredictable drug response. Higher doses are sometimes tried, but may lead to an increase in dyskinesias.

2. Enzyme inhibitors.

Also known as carbidopa, enzyme inhibitors block the break down of dopamine by enzyme systems in the brain. Blocking these enzymes is a key strategy to prolonging the effect of dopamine. The two most commonly prescribed forms of levodopa contain carbidopa.

3. Dopamine agonists.

When certain cells on the surface of brain are stimulated, dopamine, the substance PD patients lack, is produced. Drugs that stimulate these cells are called dopamine agonists, or DAs. DAs may be used before levodopa/carbidopa therapy, or added later.

4. Anticholinergic drugs.

Anticholinergics keep dopamine levels up. However, the side effects of anticholinergics (dry mouth, constipation, confusion, and blurred vision) are usually severe in older patients or in patients with dementia. In addition, anticholinergics rarely work for very long. They are often prescribed for younger patients who have predominant shaking.

5. Drugs with uncertain modes of action.

Amantadine is sometimes used as an early therapy before levodopa/carbidopa is begun, or added on to other drugs later. Its anti-parkinsonian effects are mild and it can be effective against the psychosis and hallucinations of late PD.

6. MAO B inhibitors — Zelapar® (selegiline hydrochloride)

Zelapar is a form of selegiline, a drug known as an MAO B inhibitor that works by blocking the enzymes in the brain that break down dopamine. In the past, selegiline was given to PD patients who were showing fewer signs of responsiveness to levodopa/carbidopa medication, though not very often, because the conventional tablet form lost much of its effectiveness in digestion. Zelapar is a novel form of selegiline that dissolves in the saliva and passes through mouth tissues. Because it does not need to go through the digestive tract, more drug is available to the brain; less drug is needed to be effective.

Alternative treatments.

Currently, the best treatments for PD involve the use of drugs such as levodopa/carbidopa. Alternative therapies include acupuncture, massage, yoga, and other therapies. These can help relieve some symptoms of the disease and loosen tight muscles. Alternative practitioners have also applied herbal and dietary therapies to the treatment of PD.

You’ll want to check with your doctor to find out more about which alternative therapies might be right for you.