Problems and considerations about medical therapy

Often there is a good response to drugs for the first 5 years; thereafter, problems with medical therapy become increasingly common:

• the duration of response decreases from about 5-6 hours to only 2-3 hours
  
  
• the patient may develop involuntary movements - dyskinesia - due to imbalance between dopaminergic and cholinergic nerves in the basal ganglia
  
  
• the response to therapy becomes brittle:
  • this is the "on-off" phenomenon
  • the patient only feels well for short periods of the day
    
    
• delerium induced by medication
  
  
• NICE notes that (1)
  • antiparkinsonian medication should not be withdrawn abruptly or allowed to fail suddenly due to poor absorption (for example, gastroenteritis, abdominal surgery) to avoid the potential for acute akinesia or neuroleptic malignant syndrome
  • the practice of withdrawing patients from their antiparkinsonian drugs (so called 'drug holidays') to reduce motor complications should not be undertaken because of the risk of neuroleptic malignant syndrome
  • because of the risks of sudden changes in antiparkinsonian medication, people with Parkinson's disease (PD) who are admitted to hospital or care homes should have their medication:
    • given at the appropriate times, which in some cases may mean allowing self-medication
    • adjusted by, or adjusted only after discussion with, a specialist in the management of PD
  • clinicians should be aware of dopamine dysregulation syndrome, an uncommon disorder in which dopaminergic medication misuse is associated with abnormal behaviours, including hypersexuality, pathological gambling and stereotypic motor acts. This syndrome may be difficult to manage

Reference:

1. Parkinson’s Disease.National clinical guideline for diagnosis and management in primary and secondary care. NICE full guideline.2006