Parkinson's disease

Other medications for Parkinson’s disease and how to manage medication

Medication is the main treatment for Parkinson’s disease. It is used to try and increase the levels of dopamine in the brain or to mimic the action of dopamine on receptors in the brain. The two main types of drugs used levodopa (discussed in Levodopa) and dopamine agonists (discussed in Dopamine Receptor Agonists) All the other drugs are used occasionally alone but usually together with levodopa or a dopamine agonist. They reduce the breakdown either of levodopa in the general circulation before it reaches the brain, or of dopamine in the brain. However, they are only used with great caution because they have other possible effects in the body, some of which may be dangerous.

The MAO-B inhibitors (Monoamine-oxidase-B inhibitors such as rasagiline and selegiline) delay the breakdown of dopamine so helping to reduce the ‘end-of-dose’ deterioration for people who are taking a levodopa preparation. Selegiline may also be used on its own in the early stages of treatment when the body is still itself making reasonable amounts of dopamine. It is not recommended for use by people who have postural hypotension (a tendency to develop low blood pressure when they stand up) as it can make this worse. Andrew takes selegiline as part of a cocktail of drugs including levodopa (Madopar) a dopamine agonist (cabergoline), and another drug (lansoprazole) to counteract the hyperacidity which is a known side effect of selegiline. Penny was on ropinirole (a dopamine agonist) when she was prescribed rasagiline and she believes this helped to clear the ‘fog’ in her brain.

Amantadine (a glutamate antagonist), which Tom, Geraldine and Isabelle’s mother were all on, is a weak dopamine agonist which helps with dyskinesia.
Another group of drugs is called COMT inhibitors (catechol-O-methyltransferase such as tolcapone and entacapone). They prevent the  breakdown of levodopa, so allowing more to reach the brain. Some of the people taking them said they made a great difference to their lives. Tolcapone was found to be more effective than entacapone but was at one time withdrawn because it caused liver damage in some people. It is now licensed for use in people who have not responded adequately to entacapone. But these people have to be very carefully monitored especially during the first year of its use.
Before levodopa was discovered only anticholinergic drugs could be used to treat Parkinson’s disease. They were particularly effective in treating tremor and are still occasionally used in the early years of the disease if tremor is the only symptom. None of the people we interviewed had used these drugs.
Most people with Parkinson’s disease have at some point been warned (sometimes over dramatically) that prolonged use of levodopa may in time make the condition increasingly difficult to treat due to unwanted side effects. The arrival of the drugs described above have made this problem much less likely and less worrying because they allow much lower doses of levodopa to be used.
Many had found it very important to be able to discuss the drug regimens they started. Fiona was impressed that her husband’s consultant was prepared to listen to his concerns and share the decisions about medication. Geraldine had felt confident about accepting a new drug because she trusted her consultant completely.
Some people however felt that they did not have enough access to the neurologist in charge of their case. This made them anxious about introducing new drugs into their treatment regimen.
Many people admitted that they often forgot to take their medication (drugs) when they were supposed to. For people taking dopamine agonists the result of this was not dramatic. Philip remembers not being able to take any medication for two days and at the end just feeling a bit hung over. He understood that if he needed to get rid of his symptoms quickly Sinemet (co-careldopa - levodopa combined with carbidopa) was the drug which could do this. David, who knows that it is most important for him to take his medication exactly on time, has pill boxes with electric timers. Sharon sometimes waits for symptoms to return before she takes her next dose.
People who have been on medication for many years have usually reached a complex understanding of their symptoms and the various ways in which they can manipulate the effects of their drugs.
A few people had immediate reactions after taking their tablets so they had to adjust the time of day that they took them. See 'Levodopa' and 'Dopamine receptor agonists'.
When Tom was first put on Sinemet he was impressed by the immediate improvement in his tremor. Over the years since his diagnosis in 1995 he has learnt to be very careful of his use of the drug and is now on a cocktail of medication (including levodopa, a dopamine agonist, a COMT inhibitor and amantadine) aimed either at prolonging the effect of the dopamine in the brain or counteracting the effects of levodopa in the body. To some extent he experiments for himself. One thing he does, which is not usual, is to leave off his medication at night in the hope that this will encourage his brain to continue to produce some dopamine. He has discovered the importance, at least for him, of avoiding meals and particularly large amounts of protein around the time he is taking his levodopa.
Tom has a great interest in research into the treatment of Parkinson’s disease and has a thriving charity (The Cure Parkinson’s Trust) which raises money for this. John was concerned that not enough research was being done on the people who have Parkinson’s disease. Sharon on the other hand felt that she would be wary of entering the kind of trial where the medication you were given might be a placebo. When Angela entered a trial the medication she was given made her feel dreadful and she felt this delayed her getting appropriate treatment for her symptoms. She is still in the trial and she and her husband fill in questionnaires every 6 months. She believes that progress can come only from trials and would be willing to enter another one.
Parkinson’s UK have more information about Parkinson’s drugs.

Last reviewed May 2017.
Last updated May 2017.


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