For Non-US Residents

What is Parkinson's Disease?

Parkinson’s disease is a disorder of the brain that affects body movement and emotions.

Named after Dr. James Parkinson, a London physician who first described the disease in 1817, Parkinson’s disease (PD) is a chronic, progressive disorder of the central nervous system. Once you get PD, it does not go away and the symptoms get worse over time. In general, tremor is followed by stiffness, slowness of movement (bradykinesia), and in the later stages, lack of balance. Emotional symptoms such as depression and anxiety are also characteristic of Parkinson’s disease.

PD patients have fewer dopamine-producing neurons

Although the exact cause of PD is unknown, many of the symptoms occur when certain brain cells, called neurons, die or become damaged. The affected neurons produce a chemical substance called dopamine that is important in the control of movement. Over time, the dopamine level in the brain decreases and a chemical imbalance is caused that makes movement more difficult and less fluid. By the time characteristics of Parkinson’s disease like tremor and stiffness are visible, the normal level of dopamine has been greatly reduced.

When Someone is Diagnosed

Detecting PD in its early stages can be difficult, but most skilled practitioners can usually diagnose PD accurately.

If Parkinson’s disease is suspected, your doctor will perform an assessment that consists of:

  • A medical history
  • Questions about things done at home on a regular basis such as dressing, showering, bathing, walking, and eating
  • A special exam by a neurologist

More sophisticated tests are available if a diagnosis is uncertain, but these are generally not used due to their cost and the overall strength of the standard exam.

A positive diagnosis

At first, patients will probably have a lot of questions. Is this diagnosis certain? Is it a good idea to get another opinion? Should medication be taken or another form of therapy? What does the future look like?

Doctors will be able to answer most of these questions. It is important that patients and their doctors decide on the best treatment as soon as possible. The checklists on this site will help patients talk to their doctors about important things like medication, lifestyle changes, feelings or other concerns.

Often, doctors choose to treat Parkinson’s disease with levodopa, the mainstay of drug therapy for PD. In addition to levodopa treatment, doctors often prescribe other medications.


WARNING: Because of the risk of potentially fatal, acute fulminant liver failure, TASMAR (tolcapone) should ordinarily be used in patients with Parkinson's disease on l-dopa/carbidopa who are experiencing symptom fluctuations and are not responding satisfactorily to or are not appropriate candidates for other adjunctive therapies (see INDICATIONS and DOSAGE AND ADMINISTRATION sections).

TASMAR therapy should not be initiated if the patient exhibits clinical evidence of liver disease or two SGPT/ALT or SGOT/AST values greater than the upper limit of normal. Patients with severe dyskinesia or dystonia should be treated with caution (see PRECAUTIONS: Rhabdomyolysis).

Laboratory Tests: Although a program of frequent laboratory monitoring for evidence of hepatocellular injury is deemed essential, it is not clear that periodic monitoring of liver enzymes will prevent the occurrence of fulminant liver failure. However, it is generally believed that early detection of drug-induced hepatic injury along with immediate withdrawal of the suspect drug enhances the likelihood for recovery. Accordingly, the following liver monitoring program is recommended.

Please see accompanying complete prescribing information including BOXED warning.