NICE summarise the main points in terms of decision making:
| Dopamine agonists | MAO-B inhibitors | COMT inhibitors | Amantadine | |
|---|---|---|---|---|
| Motor symptoms | Improvement in motor symptoms | Improvement in motor symptoms | Improvement in motor symptoms | No evidence of improvement in motor symptoms |
| Activities of daily living | Improvement in activities of daily living | Improvement in activities of daily living | Improvement in activities of daily living | No evidence of improvement in activities of daily living |
| Off time | More off-time reduction | Off-time reduction | Off-time reduction | No studies reporting this outcome |
| Adverse events | Intermediate risk of adverse events | Fewer adverse events | More adverse events | No studies reporting this outcome |
| Hallucinations | More risk of hallucinations | Lower risk of hallucinations | Lower risk of hallucinations | No studies reporting this outcome |
Treatment
Currently accepted practice in the management of patients with Parkinson's disease (PD) is to delay treatment until the onset of disabling symptoms and then to introduce a dopamine receptor agonist.
Dopamine agonists have a chemical structure similar to the neurotransmitter, dopamine and directly stimulate dopamine receptors.
If the patient is elderly, levodopa is sometimes used as an initial treatment.
NICE reminds us of the risk of acute akinesia or neuroleptic malignant syndrome if medication is not taken/absorbed (for example due to gastroenteritis) and advise against giving patients a 'drug holiday' for the same reason.
If excessive daytime sleepiness develops then patients should not drive. Medication should be adjusted to control symptoms. Modafinil can be considered if alternative strategies fail.
If orthostatic hypotension develops then a medication review looking at potential causes should be done. If symptoms persist then midodrine (acts on peripheral alpha-adrenergic receptors to increase arterial resistance) can be considered.
Consider glycopyrronium bromide to manage drooling of saliva in people with Parkinson's disease.
Impulse control disorders have become a significant issue in recent years. These can occur with any dopaminergic therapy but are more common with: