Movement disorders

Question 1

Parkinson’s occurs due to

Answer 1

progressive degeneration of neurones leading to a dopamine deficiency, producing signs and symptoms of the illness.

Question 2

The aim of treatment

Answer 2

is not to prevent the disease getting worse, but to improve the quality of life for people with Parkinson’s.

• 5-10% of people with Parkinson’s do not respond well to treatment.
• Treatment is started once symptoms reach a level where they are causing a significant impact on daily life

Question 3

• In the elderly, Antiparkinsonian drugs can

Answer 3

cause confusion, so should be started at low doses and doses increased gradually.

Question 4

Impulse control disorders occur for

Answer 4

Levodopa, Levodopa + DDIs + agonists.

Question 5

Drug treatment: Dopamine-receptor agonists

Answer 5

• Dopamine-receptor agonists have direct action on dopamine receptors, they include pramipexole ropinirole and rotigotine (transdermal patch – avoid application to same area for 14 days).
• Dopamine receptor agonists cause motor complications, though to a lesser extent than levodopa. They can be used with Levodopa in advanced disease, but at this point the dose of Levodopa is reduced.
• Treatment with dopamine-receptor agonists and levodopa is linked with impulse control disorders (pathological gambling, binge eating and hypersexuality). If this occurs the dose should be lowered or drug withdrawn until the symptoms resolve.
• Dopamine receptor agonists and levodopa can cause excessive sleepiness and sudden onset of sleep. Exercise caution with driving and avoid driving completely if these symptoms are present. Hypotension is common when initiating dopamine-receptor agonist therapy.
• Bromocriptine, Cabergoline and Pergolide Important safety information: Fibrotic reactions
These drugs are associated with fibrotic reactions (formation of excess fibrotic tissue). Any disease/disorder of heart valves (cardiac valvopathy) must be excluded with echocardiography before treatment. Patients should be monitored for dyspnoea (difficulty breathing), persistent cough, chest pain, cardiac failure, abdominal pain or tenderness.
• Pramipexole dose equivalence: 1mg of Pramipexole base is equivalent to 1.43mg of Pramipexole salt

Question 6

Drug treatment: Levodopa

Answer 6

• Levodopa is a precursor to Dopamine. It is given with a dopamine-decarboxylase inhibitor (DDI) to reduce peripheral conversion of levodopa to dopamine, thereby limiting side effects e.g. nausea, vomiting.
• The DDIs used with Levodopa are Benserazide (in Co-Beneldopa) and Carbidopa (in Co-Careldopa). Nausea and vomiting with these drugs is rarely dose-limiting + Domperidone can be useful in controlling these.
• Levodopa therapy should be initiated at a low dose… and increased in small steps.
• The effectiveness of Levodopa may fluctuate with normal function in the ‘on’ period and weakness with restricted mobility in the ‘off’ period. ‘End of dose’ deterioration with shorter duration of benefit also occurs. MR release preparations may help with end of dose deteriorations.
• Apomorphine (dopamine receptor agonist) can be used in advanced disease for patients that experience unpredictable ‘’off periods’’ with levodopa treatment. The patient must be taught to self-administer this drug by SC injection into the lower abdomen or outer thigh at the first sign of an ‘’off’’ episode.

Question 7

Colour urine

Answer 7

Co-Careldopa + Co-Beneldopa may colour urine, this is harmless

Question 8

Drug treatment: Monoamine Oxidase B Inhibitors

Answer 8

• Examples include Rasagiline and Selegiline. They are particularly useful for patients receiving Levodopa that experience ‘end of dose’ deterioration.
• Selegiline can also be used alone for the treatment of Parkinson’s, it may even delay the need to start Levodopa

Question 9

Drug treatment: Entacapone

Answer 9

• Entacapone is catechol-o-methyltransferase inhibitor – it prevents the peripheral breakdown of levodopa thereby giving it more opportunity to reach the brain
• It is also useful in patients on levodopa experiencing ‘end-of-dose’ deterioration.
• Entacapone can colour the urine a reddish-brown colour.

Question 10

Tolcapone

Answer 10

Hepatoxicity: advise patients to recognise symptoms (anorexia, nausea, vomiting, fatigue, abdominal pain, dark urine or pruritus)