4.9.4 Management of dementia in Parkinson’s disease

ChoiceDrugDosage
1st choice
Non drug treatment – see Prescribing Notes
2nd choiceRivastigmine capsules 1.5mg, 3mg, 4.5mg, 6mg; oral solution 2mg/mlDose:
Initially 1.5 mg twice daily, increased in steps of 1.5mg twice daily at intervals of at least 2 weeks according to response and tolerance; usual range 3–6 mg twice daily; max. 6 mg twice daily; if treatment interrupted for more than several days, treatment should be retitrated from 1.5mg twice daily

Prescribing Notes

  • There are two types of dementia associated with Parkinson’s disease (PD): Dementia with Lewy Bodies (DLB) and Parkinson’s Dementia (PDD). The clinical features of DLB and PDD have much in common and are distinguished primarily on the basis of whether or not parkinsonism precedes dementia by more than a year:
    • PDD: motor symptoms present for at least a year before experiencing dementia
    • DLB: symptoms of dementia present either before, or at the same time, as developing Parkinson’s like problems
  • Other causes of cognitive impairment should first be ruled out before considering drug treatment, e.g. infection, dehydration, electrolyte imbalance, adverse drug reaction or subdural haemorrhage.
  • Consider safely reducing or discontinuing (on specialist advice if necessary) any drugs that may be causing or exacerbating cognitive impairment, including:
    • Drugs with an antimuscarinic action, including tricyclic antidepressants, tolterodine, promethazine and oxybutynin
    • H2-receptor antagonists such as ranitidine
    • Benzodiazepines
    • Amantadine
    • Dopamine agonists
  • Parkinson’s disease medication should be reviewed with a view to maximising motor control but minimising impact on cognition.
  • Cholinesterase inhibitors have been shown to improve cognition, delusions and hallucinations in patients with DLB (which has similarities to PD). However, motor function may deteriorate.
  • Rivastigmine is the only drug for dementia that is licensed for dementia in patients with idiopathic Parkinson’s disease.
  • Rivastigmine patches may be an appropriate choice of formulation for some patients e.g. those unable to tolerate side effects of oral rivastigmine. Unlike oral preparations, the transdermal patches are not licensed for dementia associated with Parkinson’s Disease.