Feb 09, 2009 - Treatment for Parkinson's involves weighing the potential risks and side effects against the possible benefits. So it evolves with the progression of the disease and will often include a combination of the following options as well as Activa DBS therapy.
Dopaminergic replacement treatments work, as the name suggests, by replacing lost dopamine through medication, the most common of which is levodopa.
The drug mimics natural dopamine production and is cheap and very effective when taken at the onset of the disease. However, its efficacy is diluted with the progression of the illness and patients often experience 'peak and trough' cycles and 'off periods'.
There are also long-term complications associated with levodopa that begin to appear after the honeymoon period of five years. These include drowsiness and psychiatric problems such as gambling addictions, hypersexuality, hallucinations and psychosis.
In addition, many patients experience jerky, involuntary movements - known as dyskinesia - induced by the drug such as weaving and swaying movements of the torso. Such side effects are painful and disabling as well as difficult to treat.
Dopamine agonists are another form of dopaminergic replacement therapy that are often used in conjunction with levodopa. While they do not induce involuntary movement, patients will typically require a higher dosage to achieve the same benefits as levodopa.
Dopamine agonists do have a tendency, however, to induce more psychiatric side effects, particularly in older patients who may experience more severe hallucinations.
Rehabilitation through physiotherapy is also sometimes used to help patients regain their motor functions and muscle movement. However, there is limited benefit due to the progressive nature of the disease. Rehabilitation also does not treat tremors, balance or muscle rigidity.
Anti-cholinergic Drugs
Anti-cholinergic drugs, otherwise known as inhibitors, are used to prolong the efficacy of dopaminergic treatment and mitigate the peak and trough cycles.
The Catechol O-methyl transferase (COM-T) inhibitor is often used with levodopa as a second-level treatment for patients at a more advanced stage of the illness.
The drug works by allowing a larger supply of levodopa, and thus, dopamine to reach the brain. COM-T inhibitors are commonly used for patients experiencing an 'off period' with levodopa. Side effects include sleep disorders, hallucinations, loss of appetite, low blood pressure and dyskinesia.
Monoamine Oxidase type B (MAO-B) inhibitors work by blocking the MAO-B enzyme that degrades dopamine. MAO-B inhibitors can work alone and are often used as a first treatment in younger people and can help delay the need for levodopa. They are, however, very strong and can induce depression in patients as well as cause low blood pressure and flu-like symptoms. When used in conjunction with levodopa, involuntary movement is a common side effect.