Timing of medication

When treatment is given for Parkinson’s disease (PD), there are several reasons why different medications may be given at different times.

• PD is a neurological disorder with a wide range of symptoms, so each person will be given different medications to treat their particular symptoms.
• PD is a progressive disease and symptoms change over time. A combination of medications may be needed – especially in the later stages of PD – as some medications treat certain symptoms better than others.
• Some of the medications used in PD may cause unpleasant side effects and, if this happens, the doctor may change the medication or prescribe extra medication to treat the side effects.
• Most people with PD will receive levodopa at some point during their treatment. This is an effective medication that provides the brain with extra dopamine. However, when the disease progresses, there may be periods of the day when the effects of the medication appear to ‘wear off’. At this point, other medications can be added to reduce the wearing off phenomenon, and the dose of levodopa reduced accordingly.
• Because the effects of levodopa can begin to wear off, or cause other side effects, after several years of use, doctors have tended to delay the use of levodopa for as long as possible. Consequently, a person may begin treatment on another medication (such as an MAO-B inhibitor or dopamine agonist) to control the symptoms of early disease, and to delay the use of levodopa until it is really needed. However, it has recently been suggested that it is the disease becoming more severe over time, rather than long-term levodopa use, that causes the effects of levodopa to wear off. Therefore, early treatment with levodopa may be considered for some people with PD – particularly the elderly, due to levodopa’s effectiveness against movement-related (motor) symptoms. Starting treatment with a dopamine agonist is preferred in younger people, as they are prone to developing long-term complications (see sections on ‘What are motor fluctuations?’ and ‘What is wearing off?’).