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Home | Parkinson's Disease: Treatment Overview | Parkinson's Disease: Levodopa
However, the enzyme that converts levodopa to dopamine (DDC) is present throughout the body. So the majority of levodopa taken by mouth could be converted to dopamine before it has reached the brain, wasting most of the dose.
In order to stop this from happening, levodopa is now combined with another drug that stops your body from using up the levodopa before it reaches the brain. This is available in single capsule/tablets e.g. Sinemet and Madopar. This means you won't need to take as much levodopa.
The response to levodopa changes over time in many people and side-effects increase with treatment. You may get an ‘end of dose wearing off’ when Parkinson's disease symptoms return. You may also develop sudden and unpredictable fluctuations known as the ‘on-off’ phenomenon. ‘On’ means the person is able to move, and ‘off’ means that they cannot. People taking levodopa may develop dyskinesias – jerky, uncontrollable movements – during the ‘on-off’ states.
Advantages and disadvantages of levodopa + DDC inhibitor combinations
Advantages
Disadvantages
Up to 80% of patients show an initial improvement in their symptoms
Multiple daily doses often needed (the number of doses per day is dependant on may factors but it can be between 2 and 12)
20% of patients may be restored to virtually normal movement
Patients may be no longer able to drive due to side effect of drowsiness
Improvement in mood may occur
Effectiveness gradually declines over the years with chronic use
May increase life expectancy of patients due to improved movement
`Motor complications` in patients receiving levodopa for several years
Side effects include gastrointestinal upset (e.g. nausea, vomiting) and hallucinations
