Parkinson’s disease and other akinetic rigid syndromes II
There is no cure for Parkinson’s disease. The treatments available are directed at minimizing the symptoms and disabilities of the patient. Several agents have been tried to provide a neuroprotective effect and slow the deterioration of the disease, and a range of treatments such as transplantation may prove useful in the future.
The life expectancy of a patient with Parkinson’s disease is only minimally reduced.
Pharmacology
In simple terms, a reduction in dopamine and dopaminergic neurones underlies Parkinson’s disease. This dopaminergic system is antagonized by a cholinergic system. There are several levels for possible pharmacological intervention (Fig. 1; Table 1).
Table 1 Drugs used in the treatment of Parkinson’s disease
| Groups of drugs | Examples | Comment |
|---|---|---|
| Levodopa preparations | Sinemet (levodopa plus carbidopa) | Precursor of dopamine combined with a dopa-decarboxylase inhibitor to prevent metabolism outside the brain |
| Madopar (levodopa plus benserazide) | ||
| Sinemet CR, Madopar CR | Controlled-release preparations | |
| Dopamine agonists | Bromocriptine, lisuride | Broad-spectrum dopamine agonists |
| Ergot | Pergolide | More specific agonist to D2 dopamine receptors |
| Cabergoline | ||
| Non-ergot | Apomorphine | Given subcutaneously by pump |
| Ropinirole, pramipexole | ||
| Rotigotine | Available as a patch | |
| Dopamine releasing agents, glumatergic | Amantadine | Weak symptomatic effect. May help dyskinesias |
| Monoamine oxidase B inhibitor | Selegiline, rasagiline | Mild symptomatic effect. Smoothes delivery of levodopa |
| Co-methyl-transferase inhibitors (COMT) | Entacapone | Potentially augment the effect of levodopa |
| Anticholinergics | Procyclidine | Limited efficacy |
| Benztropine | Useful for tremor. Prominent adverse effects |
