People who develop Parkinson's will most likely need medication for the rest of their lives. Today, the symptoms of the condition can be very effectively relieved and through medication, the dopamine deficiency in the brain is controlled. In the beginning stages, a single medication or a combination of different medications can be used with medical treatment being started in low doses and increased gradually. Medication is always individual and can vary greatly between people and as such, there is no single, optimal treatment. You will need to work with your doctor to find the right balance of treatments for your specific symptoms with regular reviews and adjustments made as needed.
There are several different types of anti-Parkinson’s medication and they work in different ways to:
- increase the amount of dopamine that reaches the braia
- stimulate the parts of the brain where dopamine works, or to block the action of other chemicals or enzymes that affect dopamine and reduce its effect.
- The following outlines the types of medications available:
- Levodopa – dopamine is unable to cross the blood-brain barrier and a dopamine replacement treatment, known as levodopa, is administered which then converts to active dopamine in the brain
- Dopamine agonists – these imitate or mimic levodopa’s action by directly stimulating the brain’s dopamine receptors. Although not quite as effective as levodopa, they can provide good symptom control and may delay the onset of motor complications associated with long-term levodopa use
- Catechol-O-Methyl Transferase (COMT) inhibitors - these prolong the effects of levodopa doses by preventing the breakdown of the medication in the brain. The preparations available, entacapone (Comtess®, Comtan®) and tolcapone (Tasmar®) can decrease the length of “off” times and may allow levodopa doses to be reduced.
- Monoamine-oxidase B (MAO-B) inhibitors - these slow the breakdown of dopamine in the brain to produce more sustained effects. Selegiline (Elderpryl®and Zelapar®) and rasagiline (Azilect®) are the medications available and they are recommended for people who experience ‘end of dose’ deterioration when taking levodopa/carbidopa combinations. Rasagiline may also be used on its own in early Parkinson’s
- Anticholinergics – these are older medications that reduce the effects of acetylcholine, a neurotransmitter in relative excess in the brains of people with Parkinson’s due to dopamine depletion. They reduce tremor and rigidity, and can have positive effects on drooling, but have little effect on bradykinesia (slowed ability to start and continue movements). Side-effects, such as memory impairment and other neuropsychiatric complications limit their use, particularly in the elderly
- Dopaminergic - Amantadine is an old medication with weak dopamine agonist effects. It improves mild slowness, tremor and stiffness, and recent research suggests it is effective in treating dyskinesias that result from taking levodopa. It may, however, cause side-effects such as hallucinations, insomnia, ankle swelling and skin mottling.
