Medicines for Parkinson's disease

What it is

Parkinson's disease is a progressive neurological condition caused by the gradual loss of nerve cells in part of the brain that produce dopamine, a chemical messenger important for smooth, controlled movement. As dopamine falls, the characteristic movement problems appear: slowness of movement, muscle stiffness, and a tremor that is often most noticeable at rest. It can also cause smaller handwriting, a quieter voice, reduced facial expression and changes in walking and balance. Many people also experience non-movement symptoms — such as disturbed sleep, constipation, low mood, anxiety and, later, problems with memory and thinking. It usually develops in later life and progresses slowly over years, though its course varies a great deal between individuals. Diagnosis is clinical, made by a specialist from the pattern of symptoms and examination.

How it is treated

Care is led by a specialist team and is tailored to the individual, because symptoms and their impact differ from person to person. Treatment manages symptoms and improves quality of life — it does not cure the condition or stop its progression. Medicines work mainly by replacing dopamine or mimicking its action, and the timing of starting them, and which to choose, is balanced against likely benefits and side effects. As the condition advances, doses and combinations are adjusted to smooth out fluctuations in how the medicines work through the day. A crucial safety point: Parkinson's medicines must never be stopped abruptly or missed for long, as sudden withdrawal can cause a serious deterioration; if someone cannot take their medicine by mouth (for example in hospital), this must be flagged urgently so it can be given another way. Physiotherapy, occupational therapy, speech and language therapy and emotional support are an important part of overall care.